PKM airdrop multiplier for 1 BCX cards

The PKM airdrop multiplier is per transaction, so users who bulk-buy 1 BCX cards are at a disadvantage due to the limit of blockchain transactions (250 items).

As such, I recommend for such transactions to be grouped and, for a set time, be considered as one transaction for the airdrop.

e.g. all purchases for the last 10 minutes count as one transaction