Well, I went back and read that sentence several times. I was a pro at this at one time, and uncertainty of meaning always catches my attention faster than spelling. It isn’t a grammar problem, but a usage one. The sentence is grammatical as is.
Thanks for raising the point in the first place! It is always good to have people call you on issues of style, usage, & content. I have certainly embarrassed myself enough over the years by putting out poorly written & proof read documents where the gaffes killed the message and the grade. The mathematical equation for those disasters was RD=FC (Rough Draft = Final Copy).
V/R
Bill