hi there
i think you have to ensure that you establish what your client is looking for at the outset, is it an EOT, a deep clean, or a dust and vacuum, it doesnt matter whether the client is a domestic or a commercial client.
because if you are not quoting for what they want then you have less ofa chance of winning the work.
establish the client needs, then inform them of any pitfalls you see from the lower level of clean that they want, and then suggest an alternative, be consultative in your sale method, the client can then make an informed decision, and then everyone knows what is happening.
example
the side of the road car washes.
basic wash £xx.xx
standard wash £xx.xx
deluxe inside and outside £xxx.xx
the customer then decides what they want, but it is the same principle as above.
regards
martin