I would say the 2W should be used. I say this because it would be exceptional to spec 2W and there is probably good reason to do so, though I do not know that reason.
Often times people with experience with the design reason that a different value will work. Or they find that the component doesn't mechanically fit into the modified design. (I will admit to doing this myself) I suspect that the resistor periodically is dissipating 1W (1W of tolerance). If this is the case, after many cycles, even years, the 1/2W will fail.
I will share some experience. I put 2W (12V/0.15A) into a 2W resistor. I went to pick up the board and grabbed it by the resistor and burnt the crap out of my fingers.
Overdesigning is good. Cautionary tale: Mrs. Fiorina told the printer mech designers that they make the printers too good and that they should make them cheaper. The company of which she was CEO is not doing so good today.