Open the WO
hit [F9] to view only Labor
verify the Billed hours in the Q-hrs field at the bottom of the screen when highlighted on the labor job...
double click / edit the labor item after the Q-hrs is set
use the [Ctrl/H] on the screen to distribute the hours proportionally to the techs (loss or gain)
select the [Done] button at the bottom to mark the job itself as done