Before revision:  In the DMV model, we show that under a well-known condition , it is optimal to sell the first unit deterministically . Under the same sufficient condition, a bundling mechanism (which is deterministic) is optimal in the IMV model.
After revision:  In the DMV model, we show that under a well-known condition , it is optimal to sell the first unit deterministically in the DMV model and (b) it is optimal to bundle (which is a deterministic mechanism) in the IMV model.