Of course, there is one flaw with charging by the room/method of cleaning/travel etc etc, is you've got to go out on site to do a survey on every occasion = more time, more money!!
Whereby, those who do a standard sq meterage or hourly rate charge don't have to do that costly time consuming seperate survey
personaly, i wouldnt say its a flaw, i survey 95 percent of my new jobs, repeat custys i have already the details,
and in the fact you pay a visit alone does give you a number of advantages, you see exactly what you are dealing with, you can assess the logistics, you can sell yourself as opposed to a voice on the phone, you can also suggest other items been cleaned, by doing on site survey you discover exactly, what is what and a higher percentage of enquiries are turned into bookings .
Geoff