US Federal wage and hour division of the Department of labor and the IRS are who make the rules that your boss has no choice but to follow as long as you are 'non-exempt, hourly paid employees', if you are in the USA.
Your state may have even more strict rules, but the bottom line comes in when you work overtime (over 40 hours in 1 week), that overtime has to be paid or compensated at 1.5 the normal hourly pay rate, and must be paid at the same time as the same pay period for the rest of the week, as it was worked.
Of course if you are paid by the piece of work done, or strictly commission on what is billed, then you may either be an 'exempt' hourly worker, that is your exempted from the 'overtime rules for wages' or you may be legally a sub contractor, and not even covered by workers comp rules.
I kind of think this happens as much because managers are exempt from the overtime rules, so they feel everyone else must be also exempt, however this is THE one area that the federal and state governments are pretty quick to step up and let the employer know what the real rules are, and put them on notice with a hefty fine, since the overtime [you are not getting paid] for is also a wage the Government expects some taxes from, and they want their part too.