Your Alk is swinging (9, 10.3, 8.4, 9.3) and will likely make SPS dizzy and die! ha Either you figure out the % water change needed to maintain Alk or might I suggest something? Stop changing your water. Given that you just have LPS and softies, they don't consume much Alk, unless coralline algae started to take off.
I like the idea of dosing vs changing water to keep up with demand, which should be very low right now. When your rocks are all purple and your arm is tired from scraping coralline algae, then you should seriously consider All for Reef, 2-part dosing, kalk, or CaRx. Personally, I don't like changing water -- I find it tedious and unnecessary. My main SPS-dominant tank will be 3 years old in 2 months and it hasn't seen a single WC. My previous tank went for almost 7 years without a WC as well, until I did an upgrade.
Bottom line: for SPS, stability is key -- whatever numbers you pick, just keep them stable and stop tinkering with water parameters! Good luck.