Open the WO by Double clicking or F4 edit.
hit [F9] x2 to view only Labor Operations.
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/keyboard 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