Hi, I think you should carry on, WFP imo is a better clean. The customer gets the frames, vents and sills washed, not wiped, washed. On first clean I wash from the top scrubbing like mad and just get as much dirt to run down as poss, then a light rinise down after washing all frames and glass and do same on next window. I then go back to the first window and wash again and to frame I clean well and downwards again. I then rinsed the top frame and then the black seal flushing all dirtout and putting enough water on it to know pure is the dominating and then i rinse the glass I take the brush away from window and then 1-2 inch below frame I go side to side rinse and and build a head of water going down the glass then rinse down the glass....I have never had anyone complain and I very oftern am picking up work from franchise or large cleanign companies whom are not putting enough effort in to the work, I really am picking loads of work up from this, so I feel its down to the operator and the care taken in the work, I clean 12-14 a day and take my time to make sure all windows are cleaned properly, I might not do as many as some claim to do 20 or more a day on their own but I am happy with that amount and dont have any customers under £10 unless small quick jobs and have built business up on recommendations... So please just keep trying and it will work for you I promise....just put logic in to it, clean dirt so that it does not infiltrait the pure water coming down and settle on the glass (called rinsing well - not to little not to much power on rinse. All the best!