It's the total of purchases that *post* to the account during the calendar year minus returns. Fees, interest, and money-equivalent stuff doesn't count.

IME when I earn the 15,000 MQMs, I can select them (versus gifting to someone else) on the DL website about a day after my statement closing date, often before I receive the email inviting me to make my selection. It shouldn't have anything to do with payments providing that the account is in good standing.