A few comments.
I also listen at lower than typical volumes. I frequently have to fight with salon proprietors to turn it down when I audition new equipment. In my case, those lower volumes represent realistic volumes. Bach cantatas are seldom performed at 105 dB. So, Ralph, no worries! You did not confuse me by presenting the facts as dictated by physics and math. My Coincident Triumph Extreme II monitor pairing with the Coincident Franks is not a perfect in every respect set up, but it achieves my goals better than anything I have yet owned or auditioned. What I loose with reproduction of Mahler, I gain in reproduction of a Beethoven violin sonata.
Rob made an especially astute observation with respect to some of us having true timbre as the number 1 priority. Indeed, for me, if a piece is slightly amiss in this respect it is a non starter. I have quickly rejected very well reviewed equipment on this basis. I can make sacrifices in low frequency extension and dynamics, but not with timbre. I suspect this may also be something Rebbi values, based on his love for his new AN 300B.
In Rebbi's case, I am sympathetic to arguments for very high efficiency speakers. It may well be that given his musical tastes and listening volumes, he can't get what he seeks without getting into the 97-100 dB efficient range. His deCapos can certainly be bettered in that respect, and with a higher efficiency speaker he is likely to realize the improved dynamics he seeks. Also, it is my experience that the deCapos, for all their virtues, don't handle the lower octaves all that well. Both Rob and I noted issues with walking bass reproduction.
The problem is his budget. At $1500, there are going to be trade offs. If there were a $1500 speaker that did everything he wants, we would all own a pair. I would have thought something in the Tekton line might have been his best shot. His brief audition of one of the Lores was disappointing. My fear is that while he can probably find a deCapo replacement that betters their performance in one or two respects, he may find a decrease in what he calls refinement may not be an acceptable long term solution. He is not in a position to run experiments that are not cash neutral.
So Rebbi, sorry if I have spoken as if you are not in the room. I can still remember when cash flow was tight. My advice is to continue to audition everything that you can at minimal cost. Too bad you are so far away from Tennessee. I'd love for you to hear my Coincident TE IIs. The performance gap by comparison to the deCapos is startling. Be careful selling the deCapos to fund something that is a pure experiment. It is going to be easier to deoptimize in a cash neutral transaction.
If you had another $1000, i think you would have more options.
Meanwhile, enjoy what you have.