hi there
if you quote an amount of money for a job, and then deliver the service to the standard required, but within in an iproved time, then that is your benefit.
the client has accepted the price, which they have considered and accepted to be of a reanable price for the work.
i will always say to the client, that " the work will take about x time to complete, but we may complete the job within that time"
how you resource the work and complete the work is down to you.
the problem that you have with reducing the pricing, expecially to a main contractor, is that they are more likely to try a neg the price down in the future.
we have built ur reputation on delivering a quality service, at a price. and we will continue to do that.
regards
martin