Hey, cool paper spreadsheet. Did you steal that idea from someone too ?
I don't think I've ever seen velvet on marine fish, but that looks like waaay tooo much powder to be MI.
But if it is velvet you'd expect it to be dead by now.
If it is MI, it looks to me like it's cycled more than once or twice.
Hopefully others with more long-term experience will chime in.
In the meantime, good luck W