I agree the two Sarah Hills are different people. However, without quality sources, it is difficult to tell which one married Crane vs Buzzell. The FindAGrave date for Sarah Hill Crane does say she was 72 years old, but doesn't give her birth date, nor does the Crane Genealogy. There were many Sarah Hills born in Massachusetts around 1745, so it might be a different Sarah. Crane Genealogy doesn't give her parents, nor does FAG.
If there were sources tying either Sarah Hill to her parents and spouse, I would have more confidence regarding which is correct.
Ancestry information from online family trees is not always reliable.