Numbers like these are best used as a comparision between two aircraft types. As a computation of actual costs they get very dodgey very quickly.

The cost of operation contains two figures:
-Frequency
-Hourly
You need to calculate a frequency cost per departure and then the hourly cost after that.

This results in some strange figures when accurate costings are made.
e.g. From memory;
When Air Canada had both DC9's and A319's the Dc9 had a cheaper trip cost on stage lenghts up to about 1:15, after that the A319 became cheaper for every hour of stage length. Many times we were asked to downguage a flight to a DC9 (100 seats) from an A319 (116 seats). In a lot of cases the drop in capacity actually worked out to be more expensive.
The reason was that the frequency cost of the A319 was higher, but it used so much less fuel than the DC9, that over longer stage lengths it actually worked out to be cheaper.