ewan ko lang sa company mo, pero usually ang per diem ay based sa cost of living sa pupuntahan mong lugar. for example, sa US ang domestic per diem rates ay nandito.

http://www.gsa.gov/Portal/gsa/ep/con...Type=GSA_BASIC

your employer may not necessarily need to follow the rates from the above website, as this applies to companies operating domestically. use it only as your basis.