Unfortunately, in most cases the base salary is the only part of compensation that is 'guaranteed'. Overtime requirements could change after a few months, a job

Unfortunately, in most cases the base salary is the only part of compensation that is 'guaranteed'. Overtime requirements could change after a few months, a job with a longer commute might allow work from home, etc. Your 'true rate' is an interesting piece of information to consider during job search, but I do not think it should have this much weight.