Wow... I really couldn't have asked for better support. Thanks for your insanely quick and spot on responses!

I've been working in inches (not my own preference, but for US manufacturing it is easier) and haven't really encountered sizes larger than 100 before! And yes, if I just click on the number it now displays properly (for some reason I had it in my head that setting the 5 trailing zeros would stop the rounding in the viewport, and forgot that very basic operation to check the value!). I think there is still some unit conversion oddity that is going on, but it looks like the real issue is a misunderstanding I had with the UI!

Michael, I will PM you the file in it's original inch setting so that you can check the unit conversion and let me know if this seems off.

Thanks,
FDP