Straight answers on Per Diem, please

I am not GREAT at math but decent enough to know that some drivers seem to be getting screwed here.
RIDDLE ME THIS:
If per diem is 52.00 a day in a five day week a driver should get 260.00 added to his check tax free, correct?
OR
be allowed a deduction on federal taxes of 52.00 per day, Right?

If trucking companies R going to force per-diem rolled into pay it should be at the standard rate and nothing less, Correct?

Seems like companies want to pay their own makeshift rate for per-diem and pocket the Federal tax benefit that the driver should be getting.

Am I getting the jist of this per-diem deal or am I missing something?

When I worked out of state installing conveyer systems, the company I worked for payed us 100.00 a day per-diem....this came as cash and was tax free, isn't that how per-diem is supposed to be figured...tax free? i know...shoulda stayed with this job right? it was just hit or miss work...not full time.
Are there any companies that pay properly at the goberment authorized rate each day?

 

OK thanks, at least the driver getsthe benefit.