my daytona lose 5 minutes a day after changing dial

[FeelingTheBlues]

Originally Posted by Nimrod

If the watchmaker (I'm being kind) thinks that -5 minutes/day is OK maybe he just misunderstands the whole +6/-4 COSC thing; thinking, you know, that it was MINUTES! Then again, even that would be out.

I think you may have misunderstood what the watchmaker did and meant by "the watch is okay". The OP said that the watchmaker's equipment is in the back of the office so he couldn't show him but my guess (as it is what watchmakers usually do) is that he took the watch, put it on a timegrapher and tested it to see how the movement was. The machine most probably showed him that the movement shouldn't lose more than 2 seconds per day.

I find it strange that this machine isn't plugged to a printer, usually the watchmaker should be able to have the information regarding the watch's accuracy in all the tested positions on a piece of paper to show it to the customer. Still, the fact remains that this man probably tested the watch and noticed that it's supposed to run well according to the movement's test, hence our theories about the hands, the use of the chronograph function for a long time or the cannon pinion (the watchmaker could test the watch after starting the chronograph to see how the results change but the two other possible problems cannot be checked on that machine, it works with the sounds made by the watch).