Learned the hard way on my last flip that you just do not touch those old mud beds unless you have to. I always figured ripping it out and pouring self leveler would be faster and cleaner, then I spent two weekends fighting a wavy floor that still wasn't right. That inch of mortar was doing real work and half of it wasn't even the flat part you see, it was the structure. Now I just patch the loose spots and leave the rest alone.

Flat rate billing sounds great in theory, but the math you did has a hidden trap. Those two clients might have paid $2,400 more this year, but that only works if they say yes to the new deal and stay for the full year. A client who feels burned in a slow month will leave, and then you're not just missing the $200 in January, you're missing the whole year. In my experience, the fix is to keep some kind of floor under the flat rate, like a minimum monthly retainer plus extra for big projects, so the client still sees value in the slow weeks. Otherwise you swap one cash flow problem for a client retention problem, and that one is worse.