Can companies make a profit off of the per diem they charge their clients?

I work for a company that charges their clients $135 per day per tech on field jobs. The company only pays the techs $35 a day per diem and then the company pays for the hotel room (anywhere from $50 to $90 a night depending on location) however it is company policy to double up the techs and make them share rooms. So on an average job with 2 techs the company collects $270 a day from the client in per diem however they only pay out $70 to the techs and on average $80 for one hotel room. So that means the company is pocketing $120 per day on average. Is that legal? I work in Ohio but it is a global company.