Our contemporary house has a shed roof that is finished with a layer of aluminum flashing nailed through the top course of shingles. The flashing turns down and just covers the top edge of the fascia board.
This doesn't seem to have caused any problems (it's about 12 years old), but I know that most roofs don't have exposed nails -- they are usually covered by the next course of shingles, which doesn't exist in this case.
Is this a standard technique for this type of roof?
Edit: Add pictures taken from the ground - the two higher roof lines are the ones I'm questioning.
A closer look at the higher one. You can see the flashing turning down over the top edge of the fascia; it goes over the top and sits on top of the top course of shingles; it appears to have a layer of roofing cement under it.