Guessing you are a handling agent then 750. I ask you and any other handlers what you then consider to encompass your 'handling fee' price? Personally I would consider wx and notams to be included in that price. Most generally is. However, more and more we see handlers charging their set handling fee, and them charging per items for the things, which generally and historically, were handling!
Taking rubbish / trash - that seems to be charged often now. Arrangement of hotac - charged. Pax escorted from apron to car and vice versa - charge. Arranging taxi, i.e. calling one and a fee appears if it's on account. Where is the handling
Please define the services you lot group into the 'handling fee', because it is frankly getting ridiculous at some places here in Europe.