A price quoted before the phone is open is a promise nobody can keep, and on a phone that is going to another island it is worse than that, because two people would be guessing instead of one.
So the only figure you pay at the counter is the send fee, which covers the packing, the boat both ways and the workshop's assessment. That number is fixed and it is on the booking page.
When the workshop has opened it, they give us a figure and we ring you with it. We do not put anything on top of their repair price; ask to see their slip and we will put it on the counter next to yours. If you say no, the phone comes home on the next boat with nothing done to it and you have paid the send fee and nothing else.
The same rule applies to the work we do ourselves. The figure on the form is what the job costs when the phone is what we expect, you hear the real number once the back is off, and nothing is fitted until you have agreed to it.