Open turns more efficient than flips...

I am back with open turns (due to pregnancy) and I've been amazed at the overall efficiency I gain doing open turns vs the flips I've been practicing over the past few months. I am rapidly coming to conclusion that open turns done correctly can give an overall faster time in a long event like 1500m. The reason that I think they are 'more efficient overall' over the flip turn is the following: 1. Oxygen/air: you don't run out of air in tank like in a flip, as the short breath taken at the end of the pool oxygenates the body fully for the next length, so you really can 'steam through' the distance. With the flip on the other hand, I have to judge my breathing, seem to get that hypoxic 'restricted oxygen feel' now and again (even though this has improved) which raises my heart rate and by the end of 1500m, I'm in a type of oxygen debt feeling which is lung busting and quite frankly inefficient. 2. I can consistently push off the wall in an explosive fashion and then streamline for longer and even do dolphin over a longer distance 800-1500m as I have much more oxygen to play with. With the flip you have to judge it every time to the wall and out of it and sometimes get it wrong and I certainly can't do dolphin with a flip - I'm gasping for air - even though my flip is executed really smoothly and speedily! I agree that the 'execution' of the flip turn is faster (very slightly if any gain) than the open turn, BUT it's the gain in oxygen/air with the open turn that could gain a substantially faster time in distance swimming overall... I am wondering what other's think of this.