When I saved the offer to my Aspire, the T+C included “... you will earn one $20 statement credit each month after spending $20 or more in combined eligible purchases on your Hilton Honors American Express Aspire Card at US restaurants (including takeout and third party delivery services) per month, during the Purchase Period, up to a total of $220 in statement credits...”
So, “combined eligible purchases”. Anyway, it’s per month, and not per statement, so still plenty of time to put your mind at rest.
Edit: Not still paying taxes are you?