diff --git a/source/detail/xlsx_producer.cpp b/source/detail/xlsx_producer.cpp
index 27fff391..e4b5d877 100644
--- a/source/detail/xlsx_producer.cpp
+++ b/source/detail/xlsx_producer.cpp
@@ -193,7 +193,7 @@ void xlsx_producer::write_content_types()
     write_end_element(xmlns, "Types");
 }
 
-void xlsx_producer::write_property(const std::string &name, const variant &value, const std::string &ns, bool custom)
+void xlsx_producer::write_property(const std::string &name, const variant &value, const std::string &ns, bool custom, std::size_t pid)
 {
     if (custom)
     {
@@ -214,27 +214,41 @@ void xlsx_producer::write_property(const std::string &name, const variant &value
         if (custom)
         {
             write_attribute("fmtid", "{D5CDD505-2E9C-101B-9397-08002B2CF9AE}");
-            write_attribute("pid", 2);
+            write_attribute("pid", pid);
+            write_start_element(constants::ns("vt"), "bool");
         }
 
         write_characters(write_bool(value.get<bool>()));
+
+        if (custom)
+        {
+            write_end_element(constants::ns("vt"), "bool");
+        }
+
         break;
 
     case variant::type::i4:
         if (custom)
         {
             write_attribute("fmtid", "{D5CDD505-2E9C-101B-9397-08002B2CF9AE}");
-            write_attribute("pid", 2);
+            write_attribute("pid", pid);
+            write_start_element(constants::ns("vt"), "i4");
         }
 
         write_characters(value.get<std::int32_t>());
+
+        if (custom)
+        {
+            write_end_element(constants::ns("vt"), "i4");
+        }
+
         break;
 
     case variant::type::lpstr:
         if (custom)
         {
             write_attribute("fmtid", "{D5CDD505-2E9C-101B-9397-08002B2CF9AE}");
-            write_attribute("pid", 2);
+            write_attribute("pid", pid);
             write_start_element(constants::ns("vt"), "lpwstr");
         }
 
@@ -332,7 +346,7 @@ void xlsx_producer::write_core_properties(const relationship &/*rel*/)
     for (const auto &prop : core_properties)
     {
         write_property(to_string(prop), source_.core_property(prop),
-            core_property_namespace(prop).front().first, false);
+            core_property_namespace(prop).front().first, false, 0);
     }
 
     write_end_element(constants::ns("core-properties"), "coreProperties");
@@ -352,7 +366,7 @@ void xlsx_producer::write_extended_properties(const relationship &/*rel*/)
     for (const auto &prop : source_.extended_properties())
     {
         write_property(to_string(prop), source_.extended_property(prop), 
-            constants::ns("extended-properties"), false);
+            constants::ns("extended-properties"), false, 0);
     }
 
     write_end_element(constants::ns("extended-properties"), "Properties");
@@ -364,10 +378,12 @@ void xlsx_producer::write_custom_properties(const relationship &/*rel*/)
     write_namespace(constants::ns("custom-properties"), "");
     write_namespace(constants::ns("vt"), "vt");
 
+    auto pid = std::size_t(2); // why does this start at 2?
+
     for (const auto &prop : source_.custom_properties())
     {
         write_property(prop, source_.custom_property(prop),
-            constants::ns("custom-properties"), true);
+            constants::ns("custom-properties"), true, pid++);
     }
 
     write_end_element(constants::ns("custom-properties"), "Properties");
diff --git a/source/detail/xlsx_producer.hpp b/source/detail/xlsx_producer.hpp
index 992f6e6b..dd77c8af 100644
--- a/source/detail/xlsx_producer.hpp
+++ b/source/detail/xlsx_producer.hpp
@@ -71,7 +71,7 @@ private:
 	// Package Parts
 
 	void write_content_types();
-    void write_property(const std::string &name, const variant &value, const std::string &ns, bool custom);
+    void write_property(const std::string &name, const variant &value, const std::string &ns, bool custom, std::size_t pid);
 	void write_core_properties(const relationship &rel);
     void write_extended_properties(const relationship &rel);
     void write_custom_properties(const relationship &rel);
diff --git a/tests/data/15_basic_comments.xlsx b/tests/data/10_comments_hyperlinks_formulae.xlsx
similarity index 100%
rename from tests/data/15_basic_comments.xlsx
rename to tests/data/10_comments_hyperlinks_formulae.xlsx
diff --git a/tests/data/18_headers_and_footers.xlsx b/tests/data/11_print_settings.xlsx
similarity index 100%
rename from tests/data/18_headers_and_footers.xlsx
rename to tests/data/11_print_settings.xlsx
diff --git a/tests/data/19_row_and_col_properties.xlsx b/tests/data/12_advanced_properties.xlsx
similarity index 100%
rename from tests/data/19_row_and_col_properties.xlsx
rename to tests/data/12_advanced_properties.xlsx
diff --git a/tests/data/17_with_hyperlink.xlsx b/tests/data/17_with_hyperlink.xlsx
deleted file mode 100644
index b45e444a..00000000
Binary files a/tests/data/17_with_hyperlink.xlsx and /dev/null differ
diff --git a/tests/data/1_blank.xlsx b/tests/data/1_blank.xlsx
deleted file mode 100644
index e69de29b..00000000
diff --git a/tests/data/7_presentation.xlsx b/tests/data/1_powerpoint_presentation.xlsx
similarity index 100%
rename from tests/data/7_presentation.xlsx
rename to tests/data/1_powerpoint_presentation.xlsx
diff --git a/tests/data/20_page_breaks.xlsx b/tests/data/20_page_breaks.xlsx
deleted file mode 100644
index b4eb6f28..00000000
Binary files a/tests/data/20_page_breaks.xlsx and /dev/null differ
diff --git a/tests/data/21_custom_properties.xlsx b/tests/data/21_custom_properties.xlsx
deleted file mode 100644
index a46a01f5..00000000
Binary files a/tests/data/21_custom_properties.xlsx and /dev/null differ
diff --git a/tests/data/22_formulae.xlsx b/tests/data/22_formulae.xlsx
deleted file mode 100644
index e450aec0..00000000
Binary files a/tests/data/22_formulae.xlsx and /dev/null differ
diff --git a/tests/data/8_minimal.xlsx b/tests/data/2_minimal.xlsx
similarity index 100%
rename from tests/data/8_minimal.xlsx
rename to tests/data/2_minimal.xlsx
diff --git a/tests/data/2_text.xlsx b/tests/data/2_text.xlsx
deleted file mode 100644
index be394c40..00000000
--- a/tests/data/2_text.xlsx
+++ /dev/null
@@ -1 +0,0 @@
-not-empty
\ No newline at end of file
diff --git a/tests/data/9_default-excel.xlsx b/tests/data/3_default.xlsx
similarity index 100%
rename from tests/data/9_default-excel.xlsx
rename to tests/data/3_default.xlsx
diff --git a/tests/data/3_empty-zip.xlsx b/tests/data/3_empty-zip.xlsx
deleted file mode 100644
index 15cb0ecb..00000000
Binary files a/tests/data/3_empty-zip.xlsx and /dev/null differ
diff --git a/tests/data/10_all_styles.xlsx b/tests/data/4_every_style.xlsx
similarity index 100%
rename from tests/data/10_all_styles.xlsx
rename to tests/data/4_every_style.xlsx
diff --git a/tests/data/4_not-package.xlsx b/tests/data/4_not-package.xlsx
deleted file mode 100644
index 909c7b62..00000000
Binary files a/tests/data/4_not-package.xlsx and /dev/null differ
diff --git a/tests/data/11_encrypted_excel_2016.xlsx b/tests/data/5_encrypted_agile.xlsx
similarity index 100%
rename from tests/data/11_encrypted_excel_2016.xlsx
rename to tests/data/5_encrypted_agile.xlsx
diff --git a/tests/data/5_visio.xlsx b/tests/data/5_visio.xlsx
deleted file mode 100644
index 32b6589e..00000000
Binary files a/tests/data/5_visio.xlsx and /dev/null differ
diff --git a/tests/data/6_document.xlsx b/tests/data/6_document.xlsx
deleted file mode 100644
index 2d846668..00000000
Binary files a/tests/data/6_document.xlsx and /dev/null differ
diff --git a/tests/data/12_encrypted_libre_office.xlsx b/tests/data/6_encrypted_libre.xlsx
similarity index 100%
rename from tests/data/12_encrypted_libre_office.xlsx
rename to tests/data/6_encrypted_libre.xlsx
diff --git a/tests/data/13_encrypted_excel_2007.xlsx b/tests/data/7_encrypted_standard.xlsx
similarity index 100%
rename from tests/data/13_encrypted_excel_2007.xlsx
rename to tests/data/7_encrypted_standard.xlsx
diff --git a/tests/data/14_encrypted_numbers.xlsx b/tests/data/8_encrypted_numbers.xlsx
similarity index 100%
rename from tests/data/14_encrypted_numbers.xlsx
rename to tests/data/8_encrypted_numbers.xlsx
diff --git a/tests/data/16_unicode_Λ.xlsx b/tests/data/9_unicode_filename_Λ.xlsx
similarity index 100%
rename from tests/data/16_unicode_Λ.xlsx
rename to tests/data/9_unicode_filename_Λ.xlsx