Absolutely.
1. Your brain can only hold so much information. That is one plateau you will face.
2. You can only optimize your strategy so much. That is another plateau you will face.
When you reach both of those plateaus is when your maximal performance is achieved.
Many students understand that the strategy plateau exist. Many refuse to believe that the retention plateau exists. While the information we can store in a lifetime is thought to be so much as to approximate limitless, due to the short timespan allowed for study of the high volume of MCAT material, it is often useful to compare your brain to a bucket under a faucet. After a certain point, the bucket will fill up, and any new water/info you try to push in forces what is already within the bucket out. This is the retention plateau, and for many, this occurs after 2-3 months of serious content review. For some, they max out at 2 months, for others, 4 or 5 months. The issue is we don't know when you'll max out. It's not like we have something akin to a fuel gauge on your skull that goes "and that's a full tank, go go go."
On a side note:
But even when you achieve your state of maximal performance, you must contend with the fact that the MCAT is a somewhat random experience.
A. Not all topics will be covered equally, and if your retained information matches up with the topics on that particular test, you will make maximal use of your knowledge base. If it doesn't line up well, then you will not score as high as you could have.
B. Test conditions, as much as they are controlled, are still random. Your fellow test takers are random, mindsets and emotional states are fickle things, and negative events like computer failures and food poisoning occur randomly.
C. Test takers are random. You are compared to all the other people who answered that particular question, and you are compared to all other people taking that particular MCAT. If you test with people of comparable or lower performance than you, your score will be inflated. If the reverse is true and you test with people of higher performance than you, your score will be deflated.
So in other words, to maximize your score, you must be at the peak of your retention, fully optimized strategy, receive questions that line up with your knowledge base, experience no negative testing events that break concentration and hinder performance, and you must be taking the exam when a majority of your fellow takers are poorer performers than you.