Would you like to rewrite the short sentence so that I can get a clearer picture of it?

Please rewrite "can explain correlations only up to some maximum limit" so that I can get it clearer.

What I understood is: "can explain correlations only up to some maximum limit" means something like "can explain correlations at such level that the correlations can only reach some maximum limit."

I felt that I've left out some nuance. I don't know what it is though.

Context:

In the 1960s, Irish physicist John Bell proposed a test that could discriminate between Einstein’s hidden variables and the spooky interpretation of quantum mechanics1. He calculated that hidden variables can explain correlations only up to some maximum limit. If that level is exceeded, then Einstein’s model must be wrong.

More:
http://www.nature.com/news/quantum-spookiness-passes-toughest-test-yet-1.18255