hmm, I'd debate whether a purchase of something that can be bought in practically continuous increements has to be seen as "all-or-nothing". If you're buying a car, of course, you can only buy a full car or none. but when your remaining purchase volume is [0,9975], I would have interpreted the excess part of a 10000 purchase as only the 10000-9975=25.
also, the 8-week window is indicative that this will be reviewed by a human being, who would hopefully understand the intention behind depositing 25 and then 10000 (the intention behind depositing another 10k might be a bit less clear lol).
At least that's what I view as the logically "correct" way to interpret the sentence. Whether it's what the software does or not is anyone's guess.