First Baseman's glove

[DownTownTonyBrown]

I asked this question in the midst of another thread... but it didn't get noticed or answered. Can someone explain the issues with the use of a first baseman's glove? And why is this a concern in ASA rules?

Previously:
ASA
This is obviously an ASA issue (NFHS doesn't care - size is the only requirement and it is applicable to the gloves of all players except the catcher).

NFHS Penalty for an illegal glove is the same as being quoted here.

What truly is the difference between a 1st baseman's glove and all the others? Does a 1st baseman's glove exceed the size limits of NFHS? In which case it would be illegal for any position, including 1st base. Why is this differentiation important to ASA?

Incidentally, I allowed a pitcher to use a 1st baseman's glove a couple of weeks ago during our High School State Tournament. I didn't get out a tape measure to ensure the glove wasn't too big... but did I mess up?