It's such a small difference I have no idea how you even picked it up, when listening to your recording with a metronome! I certainly wouldn't be able to! In fact, most metronomes (at least the one I have) increases in differences of 3 or 4 beats per minute so I don't know how you picked up such a minute difference. Don't be so obsessed with metronomic practice.
Having said that though, you should practice this piece at different speeds to ensure the technique is good and you are in control. You can use a metronome to determine these speeds but there is no need to use the metronome while playing unless you have serious tempo problems (e.g. unnecessary rushing). Practise at speeds like 70 bpm, 80 bpm, 90 bpm, 100 bpm, 110 bpm. (I know some of these aren't performance speeds but it's still good to do to change things up once in a while).
What you need to think about with this etude is making sure you are relaxed, in control, and focus on the musical things: shaping the melodic line with all its interesting contours and harmonic nuances!
Keeping that in mind will make for a musically engaging performance, rather than obsessing over the smallest fluctuation in speed that no one will notice anyway.