| The answer to the second question is no, that depends and who defines properly trained? A good tuner can work wonders but a bad tuner can wreak havoc and both may believe they are doing it right.
A lot goes on during a dyno run. A true tuning center will make several runs at various throttle positions in order to get the F/A correct at that throttle position. They will have a long probe that goes way up into the header portion of the pipe so they can get the best F/A reading possible. Depending on the operators skills and pace, it may take an hour or several hours.
On an older Dyno like ours, you end up doing a lot of testing and interpreting graphs, making changes, make a run, make.....
The real test is whether or not they guarantee to get it right and does it run right afterwards. | 
