Yes, run time on both IP and BP is excellent, with best time being at higher resistance/voltage. If you like 10w, run a 3 ohm near 5.5v, not a 1.7 ohm at 4 1.
If you want to be able to go all the way up to 15w, use a 2.5 ohm. That reaches 15w at 5.5v, still provides very good run time at lower voltage/power.