Yes, that's exactly what you do. Make sure you hold it where you AIMED first. The tricky part comes when you have moved one of the crosshairs, as there is a tendancy to re-align it.
Just hold the rifle firm to the stand (VERY important) and let him adjust. You'll have to tell him if it needs to go right, left etc.
Like I said, this will get you very close and you can fine tune it from there. Saves a lot of ammo.
Some scopes have a tendancy to "hang" when adjusted so you might need to "tap" it lightly at the adjusters to make sure the crosshairs have settled.