Rich,
Yes, my Win32 port also uses the C parser and there are some FOTDs that don't render right there as well. I have gone over the C parser code at one time attempting to find something offensive that would lead to the difference, but I didn't spot any obvious errors in all my reviews. I'm not an x86 assembly guru, so I haven't really studied the x86 assembly parser code and attempted to correlate it to the C code.
The major difference is that the parser assembly code uses 80-bit real numbers in the FPU and maintains the results during all calculations at 80-bits. The parser C code uses 64-bit real numbers. There are also a bunch of additional optimizations that the assembly code does that we would like to implement in the C code. Jonathan