I completely agree with @dvskier. I had the same situation and timing on use of double boot, and went to same combination of Profile and HRTP back binding. Seems to release when it needs to, both feet are comfortable.
My back heel has always lifted, which resulted in premature wear on the back binding (or intense blisters on back of heel!)
Used the new combination all last year very happy with it, finally feel that variability of back foot placement in binding is no longer an issue.
Side benefit is that this combination is somewhat less expensive than dual boot!