I don’t doubt your word on this, but it makes no sense that way (I realize making sense might not be required in NY). If the defendant does not have to be found guilty of the related felony to extend the statute of limitations on the misdemeanor, the whole concept of s.o.l. would be meaningless. Prosecutors could gin up a felony charge on something preposterous they know will result in not guilty, just to extend the s.o.l. on misdemeanors.
Doesn’t work that way. To be convicted of the felony they have to prove the felony. They can’t convict of a misdemeanor after the SOL for the misdemeanor has expired, regardless of whether they can still prosecute for the felony.