Yes, I have received commenst on posts after said post had already been paid out. The way I look at is: each comment, in itself, is like a "new post." So if I go to a post that is a year old, but make a comment on it, and that comment earns any upvotes/ payout, I will receive that payout 7 days from that point. I'm not sure if comments also "stop" there; i.e., after they're paid, I'm pretty sure, like posts, they also end. It has something to do with how the blockchain is set-up and accounts for data. There has to be some "cut off point" where the system can account for things or it would just run on and on and I don't think we have the tech for something like that quite yet... But we will.