This isn't a bug in HonorFu so much as it is in Glory-2.0.
Edit: never mind.
Temporary fix: Change lines 906-916 in Glory-2.0.lua to the following:
That gives the correct weekends for January. I'm not sure if it works for the rest of the year. I've modified my local copy, but am not going to touch the SVN version without a response from ckknight or someone else knowledgeable and authoritative.
I have no clue. I played around with my local copy of Glory until I found something that made it work for January. ckknight responded on IRC that it wouldn't be a horrible thing if we had to update it again next month if it doesn't work for it too, so I went ahead and committed my Glory changes.
If someone else can work up a better algorithm for it all, wonderful.