http://www.irs.gov/publications/p463/ch01.html#en_US_publink100033764These are the federal government rules for travel expenses.
Whenever they refer to something as being deductible, it is equally true that the employer may reimburse it tax-free (in which case it would not be deductible from income, but you wouldn't have to report the reimbursements as long as they follow the same rules.)
This is a quote from that publication.
"Incidental expenses. The term “incidental expenses” means:
Fees and tips given to porters, baggage carriers, bellhops, hotel maids, stewards or stewardesses and others on ships, and hotel servants in foreign countries,
Transportation between places of lodging or business and places where meals are taken, if suitable meals can be obtained at the temporary duty site, and
Mailing costs associated with filing travel vouchers and payment of employer-sponsored charge card billings.
Incidental expenses do not include expenses for laundry, cleaning and pressing of clothing, lodging taxes, or the costs of telegrams or telephone calls. "
It MUST be noted, however, that an employer is not under any obligation whatsoever to reimburse anything. If they do, they are not required to reimburse them in full, or to pay the maximum per diem amounts. They can also decide to reimburse some expenses and not others. They are only bound by their agreement with you (contract) and the law. It doesn't matter even a little tiny bit what other employers have agreed with their employees to reimburse. You don't work for those employers. If you think your contract is unfair, you should not have signed it. You can ask to renegotiate. Failing that, you take what they give, and don't sign the next contract unless you agree to it.
You are walking on the edge right now anyway. If you have leased a house or apartment, and don't have a paying job back home where your other house is, then your tax home is probably right where you are at this minute - meaning that you aren't entitled to any tax-free reimbursements for any meals, lodging, or incidental expenses at all.
Duplicating living expenses is not enough to determine eligibility. Lots of people have two residences. Only one of them is their tax home. Maybe neither of them is their tax home. If you make money in one place and not at another, guess which one of the two is your tax home.
If I were in your position, I wouldn't cry too loud -- especially to the Federal Government of all places -- for fear that they might actually listen. It won't take much for them to get an IRS determination that you aren't entitled to what you have been getting, that you owe back taxes and penalties, that you need to repay the allowances that you have received, basically that you have been working for nothing. Take this as an expensive lesson and move on.