1. I have nothing in particular against using paypal. For 10 years on ebay, I just got in the habit of using postal money orders and I don't like change. Most sellers still accept them, once in awhile it's a problem, but I don't buy that much on ebay anymore anyway. I have heard a lot of horror stories about paypal and I just don't feel I need it that badly.
2. I didn't ask the seller to elaborate, but my feeling was that the description of gum "falling out the bottom" of the packs was really a description of the orange packs in the other lot he was offering, which were 85-fold and did appear to have open folds. The description of "falling out the bottom" really doesn't make sense for 21-fold packs, so I'm hoping they're really in decent shape.
3. I already sent out payment for the auction so there's no reason for a re-listing, I can only assume he has a bunch of these and is selling them in lots. If that's the case, I'll probably buy a few more in the hopes of getting some in the nicest shape.
4. 85-fold 10th series packs are extremely common. 21-fold 10th packs are not perceived to be worth more, but in my experience they rarely turn up much anymore. Particularly ones like this with the brown quacker can. Again, that's just my perception as someone who has been looking for them, they have no higher value in the marketplace as evidenced by the ending price for this auction.