Done it myself, took a few minutes and managed to do it from inside the house.
Noooo, do not agree at all that I pay for a maintenance clean, I pay £15 a month to have my windows cleaned.
Bottom line is different people have different standards of work.
correct but different standards of work come with different price tags you will/should already know this unless your a start up (are you?).
If hes doing a good job (which you say he is) then hes doing it to the right standard for what hes priced for.
If you want extra work pay for it!!! thats simple business you would not/should not do it in your business if it cost you more time and money unless for very good reason, you arguing on a point that at the end of the day is simple to understand.
You left something which became a problem end of, nevxt time you see something dripping fix it before it becomes a problem for which you then are trying to push on your window cleaner, hes not at fault here this is your failing, I can understand your thought process as I deal with people like you a lot, but I explain where the problem comes from, and this being them/you (hard to swollow yes) BUT THE TRUTH yes.
My standards are very high before you think your above me or our standards of work, also my customer service is spot on I take great pride in this aspect of my business.
If a customer wants more doing of a job they pay for it, thats simple business, really is that simple, think of it the same way as your business and stop trying to be tight which I feel you are being on this ocassion. No disrespect meant at all when I say this, I am just reading wat you have put, maybe you just don't understand otr thoguht different from what is offered to you.
I'm just being honest as well as frank from what I have read. I would explain this in a totally different way if you was a customer of mine but boils down to the same thing.
Hopefully you can now see froma window clears point of view.
Respectfully
Ian