It either did not actually happen, you are not recalling the actual comment correctly or you misunderstood what she said.
Surely you understand the tenuous nature of “I think I heard this said somewhere at some time back a year and a half or maybe two years ago....”
That kind of statement is useless without a solid reference.
I think that you are correct. I've spent a couple hours or so at google and I cannot find the webpages where I initially read about that online; however, I did find that silly API story in many of the searches I attempted --- so what I believe occurred is that again & again & again, when reading about Barack Obama not releasing his long form birth certificate that I'd read quite a few times that "Michelle said... blah/blah" --- because I found one instance which rang a bell, and it still has to do with the FAKE API story, something about Michelle saying there was NO LAW which prevented her husband from becoming prez.
I am pretty positive that you are correct, that while I was reading about the Certificate Scandal, that I read many postings about Michelle, which had to do with the phoney FAKE API story, but at the time I read the posts, they didn't mention that "Michelle said..." in reference to the fake planted API nonsense.