Generally if you're finding it difficult to stay upright at the surface with a back inflate you have way too much air in the bc. It isn't unusual for new divers to get in the habit of coming to the surface and filling the bc until it's about to pop. With a jacket bc it squeezes you tight and makes you float high. With a back inflate, it pushes you forward. In both cases it is unnecessary.definitely more work on surface to stay upright.