Yes, the old version writes the same value on the two locations, more specifically the total of items in the cross-reference table.
In code, as far as I see, the new MindFusion.Pdf still does this, only it's now writing the last index instead of the total amount of items. It's using seemingly the same value on both places in the PdfHelper class:
(arg as PdfDocument)._helper.CurrentId();
Here's the content of the cross-ref table and trailer for two pdf's I've been using as a reference:
Generated by the 4.3.1 code:
xref
0 18
0000000000 00000 f
0000000017 00000 n
0000000119 00000 n
0000000185 00000 n
0000009617 00000 n
0000010728 00000 n
0000010844 00000 n
0000010960 00000 n
0000011076 00000 n
0000011192 00000 n
0000011308 00000 n
0000011425 00000 n
0000011542 00000 n
0000011659 00000 n
0000011776 00000 n
0000011893 00000 n
0000000541 00000 n
0000012010 00000 n
trailer
<<
/Size 18
/Root 1 0 R
>>
You can count 18 entries in the table.
Generated by the new 5.x code:
xref
0 13
0000000000 00000 f
0000000017 00000 n
0000000121 00000 n
0000000187 00000 n
0000000469 00000 n
0000000717 00000 n
0000000769 00000 n
0000001017 00000 n
0000001069 00000 n
0000001273 00000 n
0000001503 00000 n
0000001719 00000 n
0000002838 00000 n
0000003138 00000 n
trailer
<<
/Root 1 0 R
/Size 13
>>
You can count 14 (!) elements in the table
My customisation simply adds 1 to the CurrentID() at both places where it's used in the PdfHelper class.