Is there a minimum threshold for reward payouts?

I'm still pretty new to Steemit and still getting a hang of the platform. I've had one post that really seemed to connect with people and got a nice reward, which was gratifying. Some of the other interactions I've had, such as some interactions in replies, didn't involve as many upvotes but seeing the little "$0.01" projected reward in the UI had me at least looking forward to experiencing more cycles of the "create content / get rewards" cycle that makes the Steemit platform unique.

However, after seven days I didn't get any rewards related to those comments and the UI now shows them as worth $0.00. Poking around on this upvote calculator what I suspect was happening is that the reward was more like 0.005 which the UI was rounding up to 0.01, but I'm curious if there's some kind of threshold effect where the system doesn't issue these "half cent" rewards (or maybe other quantization effects with very small rewards). I'm not really concerned about getting a payout, it's less than 1¢ after all, I'm just curious how the system works so I can set my expectations (and also maybe avoid "wasting" my newbie voting power on things other people are unlikely to see and upvote, such as deeply nested comments) (and, yes, there's more to an upvote than just its interaction with the reward system, but it's hard not to focus on that aspect while I'm still getting familiar with the platform).