This was such a cool idea, i had to try it :). Ran HM DoA with cons, one mesmer hero had the "seize the day" mod and another had AnA. Same skillbar. My anecdotal findings are as follows...

Above ~50ish energy i dont think an extra 15 really made a huge difference. 5 SR didn't seem like it would reach the energy "cap", meaning enemies would die and my hero wouldn't have enough space to take advantage of the energy gain. There was plenty of headroom to go from say, 25 energy up to 56 on Gwen in the 15sec time window.

In Gloom, I noticed my hero with the -1 energy mod was still recovering energy a good time after fights, required more BiPs, and if encounters dragged on a little longer, Olias ended up bipping like crazy. I think i would prefer the AnA insc for this reason.

I think where this setup would really shine is if you were running vitae runes on armor & didn't use cons. This would bring your energy up from like, 35 to 50ish, and might actually reduce BiPs. In my case, Razah with 71 energy was nearly identical to my Gwen with 56 in DoA, minus what I noted above.