Louis,
From the testing that I have done, between two programs, I think the issue is really in the details that were provided in the GEDCOM 5.5 Documentation. Technology has changes, and the developers, over that time, had not gone back to look at that document and ask questions or tightening up the ...
Build a BetterGEDCOM or learn GEDCOMBetter? - Blog comment by hrworth - 5 Jan 2011