I think it's worth getting very specific about if we're talking about nominal payroll or luxury tax payroll for these purposes.
Thankfully there aren't any huge backloading considerations for existing contracts, but the calcs can still make a difference. That 180 million you quoted is basically nominal payroll(guarantees + arb estimates + pre-arb buffer to fill the roster), but not inclusive of the roughly 20 million of player benefits, Minor league 40 man salaries, and pre-arb bonus pool payments that count towards the luxury tax.
This matters because if we're talking about the ceiling being 235ish *in relation to the luxury tax line*, a nominal payroll of 235 would put them about 15 million over the tax line. But if 235 *luxury tax* payroll is the ceiling, then Jed has 35 million on the absolute high end to spend, and a mere 20 million on the low end.