Chopins Prelude in E minor - Sheeterror?!

Chopins Prelude in E minor - Sheeterror?!



Well, in lesson nr 16 Andrew talks about turns. And whenever that ~ is written, you do a turn with the note it is written over, as the centertone. BUT, in this case, I have seen vids on youtube, and they dont sound the same as when I do the turn with that centernote.
They do however sound the same, if I do the turn with B as the centertone. Is this just a sheeterror, or is there an other way of reading that ~? My theory is that I got an errer in my sheet... Well, I guess Ill play by ear, couse playing like its written Is wrong

And that x shouldnt be there aswell... Couse it is a G that should be playd, and not an A... Hmm... Tonto!!

Or am I wrong? Hehe, dont think I am
But can never be sure, cot t dobblecheck!