Yeah, but fuel usage does not vary in AM, afaia...
Veeeeeeeeery roughly the new aircraft maintenance cost is 1% of the purchase price per year. So if you buy an aircraft for, say, 100.000.000, the maintenance will be _roughly_ 1.000.000 for the first year. The pure maintenance cost will increase by about 0.0025% of the purchase price every year, so it's 1.0025% for the second year, 1.005% for the third year etc...
Added to this are the technical staff wages which are the following: (Number of aircraft divided by 3 multiplied with 3500 multiplied with half number of bases) plus (number of aircraft divided by 3 multiplied with 2500)
I hope i got it right now, it's just so many zeroes that I'll take no liability if I missed a digit somewhere.