Hi Rob,
Overall I believe this second rendition has come a long way beyond your first recording. This is much to commend here. Of course, we as pianists are never "done" with a piece. We invariably find new insights and possibilities in any piece of music, even if we play it for a lifetime. So yes, we can always find something to reinterpret or improve somehow.
You certainly have a greater overarching artistic concept of the piece now, and your execution displays both a fine technique and much expressiveness--a potent combination. This Op. 39, No. 5 is my favorite of all the Etudes. I have it on my own "repertoire to do list", but have not yet tackled it, although I have read through it a few times.
There is only one thing that jars me in your recording. It's that final sforzando E flat octave. Looking back to page 6 starting at dolce, the piece, despite its earlier turbulent hyper-romantic theme, becomes instead anticlimactic, reflective and introspective. This section is like a long, extended coda, fading away in the last two measures down to pp dynamic with a very thin texture of writing, a whole note in the RH and a quiet rocking arpeggiated figuration in the LH. I have the MCA edition edited by Alfred Mirovitch, but based on Rachmaninoff's own meticulous editing. (I like this edition because it includes the two etudes discovered in Moscow in 1947, Op. 33, No. 4 and Op. 39, No. 6. This was the first edition to include them.) At any rate, that loud octave with which you end the etude is not indicated in this particular edition. Then I checked the Kalmus edition--it doesn't appear there either. Nor have I ever heard it before in any other recording. Does your edition show otherwise? If not, I would suggest that you think about eliminating it. In my opinion it's a jolt that drastically shatters the soft, sensuous spell that is cast as the piece winds down in a state of relaxed afterglow. It just seems so incongruous. If you were to include it in performance for a jury, audition, competition, or recital, I think it would raise some eyebrows. Again, though, overall I'm quite impressed with your performance.