This could be very tricky, esp. in the light of the current economic situation,
i think you will have to grin and bear the prices for a few months otherwise the custy's will
think you are pulling a fast one and just money grabbing.
those houses where the old windy missed are a little easier, do just the windows he did, but
speak to the custy, either on the day or go back and explain the wfp and the extra windows that
can now be done and adjust the price accordingly.
change things to quick and you will lose loads, be smart, so your reliable and do a top class clean and maybe to sweeten things offer to clean the odd bit of facia ( like the front porch ) once every 3 months when the price goes up
the custy will need to see a benefit to this, remember they are used to low costs ( even if it was cr@p work )
so changes will be tough
good luck
Darran