Megillat Esther

Question

About 200 years ago, 2 variations crept into Ashkenaz Megillot. Bifnehem/lifnehem (9:2) and laharog/velaharog (8:11). They are written the "wrong" way and read both ways, two times, according to Ashkenaz custom. To my knowledge, Sephardim do not know of any variation in these verses. Even Ashkenazim know which is the right way; it is just a custom to read it both ways (first as written, then the correct version). I am Ashkenaz, but I think this custom is a minhag ta'ut and it in fact has led to Megillah readers reading the wrong way only (as written) and not repeating the correct version. I defer to the minhag of the tzibbur when reading in shul, but if I read for someone privately, must I repeat these pesukim?