No idea why they would be different. I would however think that 599 is correct and the rest should be switched. The "Washington NL" cards were in the first few print runs and the corrected San Diego cards came later. So, being the first cards on the market should give them the "a" denotation.
For the Large Print, Small Print...look at San Diego Padres under Freisleben's name and you'll see the difference in the size of the print.
Always looking for baseball variation/error cards and anything Garrett Whitley or Ian Anderson