Manipulation of a hairspring/regulator on a watch is achieved by...

Manipulation of a hairspring/regulator on a watch is achieved by the watchmaker with extreme care and understanding of the process before them. the use of a timing machine that knows its frequency and displays it on a tape to show its performance/error is accounted for by setting the regulator with a positive force.
temperature, gravity, shock, and friction ect.. are accounted for in the error.
i see the comparison in the tape. +10seconds a day for a run of the mill wind up watch, 0seconds difference of error in all positions of wear is the goal for a master in this field.