can a salaried mngr. check be prorated if time is short by minutes

Under Federal law, the employer could dock your pay based on the hours worked (or not worked) even if you are salaried.  This by itself would not violate federal law.  BUT, the danger for the employer (and therefore possible benefit for you) is that when your employer starts treating your pay as if you were hourly, it potentially exposes him to having to pay you overtime pay for working over 40 hours a week.  The employer cannot have it both ways in terms of getting you to work over 40 hours without having to pay overtime, but then docking your pay when you miss a few hours here and there. It is worth it for you to meet with an attorney to explore this in more detail so you at least know your options