Some details to consider first are:
1.) How many in your crew?
2.) How many windows can one person clean on the outside with a WFP in 1 hour?
3.) Have you calculated your business’s minimum rate per hour? (What you need to make per hour to cover your overhead, and make a survivable wage before an actual profit?)
4.) What are you options for cleaning the interior? Pole everything? Ladders? Indoor motorized scissor lift?
I am in Central Florida where the prices are on the lower end of the spectrum so normal route work is $1.25 per pane per side. I have been pricing WFP at $2.50 for the first level and then adding $1 for each additional level consecutively. My most recent job took 3 hours including set up and break down of the WFP for 126 windows, (40 of which were on the second level). I charged $190, my minimum per hour is $50 so I netted a profit of $12/hr. Same windows on the interior were done with a pole and trad tools so it took me 4.5 hours. I charged $225 so I hit my $50/hr minimum, so next time I need to assess my technique and efficiency as well as raising the price by .50-$1 per window for the interior.