CBR1000F - L (1990) CARB SYNC BALANCE 2

In someone elses vid they did not balance at idle they did it at 4000rpm but as they let it fall it went out of sync at idle, they wanted smoother running at motorway speed, is it norm for carbs to be out of sync at different rev ranges?
How often does this need doing, im thinking about investing in a Carbtune set and wondered how much it is for a garage to do same job?

If I had to do 2 separate tests (sync jobs) again...
Guages = 1 hour
Carbtune Pro = 40 mins (with greater accuracy to tollerance limits).

The carbtune Pro certainly seems to be the better option.What was ther time difference between the two units?