It might be better to give them the "option" to remove it themselves instead of expecting them to do it. Because what they are going to do is add the cost of what they pay the one or two men needed against the estimate. You may lose the gig like that because the others bidding on it probably won't do that.
Give them x-amount for you pulling screens (from the inside), x-amount for pulling from the outside, x-amount for them to do it.
Don't know how disabled the ones who live there are, but they may be able to pull the screens out on their own?
Just make sure that if they choose an option to where you aren't pulling screens, that if a screen is still on the window that you are skipping that window.
If they leave a window open, (if you are wfp'ing the job) that window plus the ones(s) above that window will be skipped and not revisited.