Its your call, how much do you want the job
Do you have to clean frames? Can you explain and get an addition on price for first clean , or put in a good price and swallow the extra graft on clean 1 in order to win the job
School work is generally very cut throat both with competition and with budget
Talk to them and see how understanding they are to get a feel for what you can get away with for the 1st clean
I have just lost a school as it was underpriced and done to infrequently to make any money also only wanted doing in holidays so when i am busy i struggled to clean it, wasnt sorry to see the back of it , so dont underprice you will regret it