The salary floor means that even if your total expenses with salaries are close to zero, you will pay the salary floor.
So I don't know if you say this in Portugal, but in Brazil we would say pode tirar o cavalinho da chuva if you are expecting a refund.
The idea behind the salary floor is to limit the ability of teams to save money by performing a losing season on purpose. This kinda makes tanking harder.
Seeing from a bright side, you can hire a 148k player and still pay the same wages than you would pay with your current roster...