The etudes you mention can be learnt in very short spaces of time.
op10 no1 can be learnt in a night by a lot of people, it's all arpeggio's, in different keys, some harder than others. It is short, and once you have the technique it just floats along. If you spend an hour on the 1st page learning it in every key, you'll learn the etude in no time.
Op10 no 8, the middle section is the only really tricky bit. The rest is just arpeggio's.
Op10 no12, that aint that bad, it's just LH strength.
Op25no6...Ok very hard, but again, if you have a solid double third technique in the 1st place, it can't be that bad, it's very easy to learn, just hard to play well.
Op25no 12, thats easy to learn, one of the easiest Chopin etudes, it is all the same.
I think the notes should be there after a very short space of time if you are at a conservatoire. To play them well will take a long time. I've seen people learn them fast, and not just asians. Just because the person you mentioned that done this was asian, doesn't mean that he/she is in any way superior.
Non Asians have learnt things at mega speed as well, Artur Pizzaro learn Brahms 2nd concero in 3 days!!! And performed it. Thats what I call impressive learning skills!