what are the average prices foe houses then,
if they are low that could be could be your problem,
how long have you had the clients and when was the last price increase,
also do you do frames and sills, if you do say i do all of this at no extra charge for x amount, and i havnt put them up in so much time, i would like to put them up 1-5pounds depending on what you can get about with
but if you dont do them increase the price and say you will do the frames and sills, bit more work involved but youll earn more moeny