The speed and the money madness kicks in with WFP, results come in second. Also the saftey aspect is the old excuse.
I use both trad and wfp and give my customers quality cleans first and been wfp 2 years now, it's not all it's cracked up to be.
If you want to charge silly money for the time taken to clean and you can get away with it then go for it, but I have been in the business 20 years and results come first and a fair wage for the days work.
Example: last week someone asked a price for a shop window and someone came back with £8.00 for 2 minutes work, this is ripping someone off and you can argue the toss till the end of time but it's still a rip off.
Adam