United Radio QSL Bureau are very much aware that we have to make sure that QSL cards are valid for as many Award programs as possible. It is not always possible to keep everyone happy all of the time. So whether you are working towards DXCC, IOTA, QRP or whatever award where QSL cards are required I will always try to accomodate your needs.
I have recently exchanged several emails with a few QRP operators who request their QSL reports to be made out as /QRP. I would like to make it quite clear that my policy is to always write the call sign in the format that the licencing authority have licensed your Amateur Radio call sign. As far as I am aware no licencing authority issues /QRP on the licence documents. I think you would agree that if i started calling as M0URX/QSL you would think it was not correct and you would be right. Q-Codes are NOT part of your call sign! Neither is it my job as a QSL Manager to verify the power of your transmitter.
If you want a specific contact out of 5 in the log to be on a separate QSL please let me know, and providing you pay the correct postage for the amount of QSL cards you need then I will try to do this for you correctly. I have also communicated with a QRP club who have said that for their awards the QSL cards do not have to have /QRP and is down to the claimaint to verify which QSOs on a QSL are QRP.