The question that has to be answered is this: When does company representation end for the tech- When he leaves his last job or when he gets to the shop or home? If the answer is when he leaves his last job, then is he free to do what he wants with the work van ( go shopping, pick up kids at school, stop at the bar for a few beers , etc) on his way home? If he's not allowed to do anything but go straight to the shop or home, then I believe he then is still on the clock.