Unfortunately, with allowables you get what is written - it is all in what the Nationals keep. When bidding - use a good cost estimator and add for the extras like height or steep or whatever you can think of. Try to determine what needs to be done and how much time you think you will need. Look up prices of supplies you need to make sure you cover it all, if you need to rent equipment - be sure to factor that in.
That being said, watch the companies you work for. Some will give you more money, but the headache of dealing with them is not worth the hassle. Others may pay less (cause they are third party) but they can do more with your pictures and work more for you and just so much less stress.