Here's my experience. I had a knee replacement in October last year and hit a plateau in the degree of bend at 95 for almost a month. (You need at least 95 to do stairs and get up from a chair, etc.) However, my doc was looking for 110-120.
My difficulty in achieving that bend was that I couldn't take anti-inflammatories due to prior stomach ulcers. So I was swelling more than most patients. He mentioned manipulation; I said let's wait and see when the swelling goes down more. He also mentioned that manipulation doesn't always work.
Long story short, I did not have it. The swelling subsided, and within another month I achieved a greater degree of bend just by activities of daily living and my exercises.
A number's just that: a number. Can you do the things you aimed to do with this surgery comfortably? Is you leg getting stronger every day? Sometimes the answers to those questions are the best guides.