Question about timing belt replacement method
 

The Volvo instructions for replacing the timing belt state that before removing the old timing belt you must rotate the crankshaft until the marks on the camshafts line up with the notches on the top timing belt cover.

But what if I were to first mark the old timing belt, camshaft gears and crankshaft with white-out, remove the belt, transfer the timing belt marks to the new belt, and install the new-belt making sure to line up my marks? Would it still be necessary to rotate the camshaft before-hand to line up the built-in camshaft marks with the notches in the top timing belt cover? It seems to me this would be unnecessary since all you care about is keeping the camshafts and crankshaft in time with each other. The white-out method should guarantee that, right? Or am I missing something? This is my first timing belt change so I want to make sure I don't mess it up.

Thanks.