How one gets a keg down from "burst carb" pressure to "chart pressure" (which hopefully is also "dispensing pressure") really doesn't matter, as long as it happens before the keg is tapped. Otherwise one ends up with "projectile beer", which is never a good thing
That one caveat is a keg filled to within reach of the gas dip tube. In that case one should close the regulator shutoff valve first, then turn the pressure knob down to
below "chart pressure", then pop the keg prv, then open the regulator shut-off valve, and finally dial up to chart pressure. This will keep beer from flowing up the gas line to the regulator whether there is a backflow-preventing check-valve inside the regulator shutoff valve or not...
Cheers!
