After I encountered some obvious cases, where I get much less points credited, than what I paid for, I calculate each stay (deduct VAT and service charges, take google E/R of the day I checked out and convert to EURO and multiply by the factor for according property).

This year I had a stay, where I got over 30% short...it was adjusted after my complaint to the hotel and they claimed some system error..

but from which difference is it feasible to complain? I tend to complain from a shortage of 3-4 %...Am I too greedy?