I wanted to post an update!
Last week I had readings of 5.3 for nitrate and 0.05 for phosphate, woohoo. It had been a long, long time since I had seen any detectable amount of either, but I learned that this can be OK. I just wasn't sure if there was/could be a problem or if I was potentially (slowly) starving my system, though the corals, coralline, macro (and GHA) seemed to be fine.
Still, I had let the filter floss sit for longer between changes (more like 5-7 days, instead of every other day), increased fish food slightly, but really just added things like Reef-Roids, the PhytoChrom, and CoralAmino into the mix.
Yesterday, I had readings of 9.5 for nitrate and 0.10 for phosphate, lol.
So, I'll be doing a 5 gallon (roughly 25%) WC today to bring those down a bit, and maybe now I will keep on with the feeding regime but go back to changing the filter floss more often. I'll do that for a bit, check numbers one more time, and if it's all good them we'll keep on with that and not worry about those numbers, unless the tank gives me a reason to check.
Thank you all for your advice. I learned a ton from this thread!