It checks out with all the usual precedence rules. USD/TB/month is the same as USD/(TB * month). Really pedantic physicists would probably write something like USD.TB⁻¹.month⁻¹ which is, again, the same thing. Unless it is TiB and not TB, that would make the plan about 9% cheaper ;)
A physicist generally should use the metric system. SI units convert to s⁻¹ from month⁻¹. Usually put the metric prefix first so T⁻¹ becomes pico. 2.6298e+6 seconds per month so pico becomes atto. Can't use B because that is magnetic feild in Tesla in SI units. $ is perhaps not as clear as USD, but feels like a better symbol to me (ideally with USD subscript but hard you write that here). I'm not a physicist, but generally I expect a physicist to use whatever is least ambiguous: which in this case is what was given (not my terrible attempt to convert to SI units!!!)