When asking a simple question like, "How much did I make last year" there are, unfortunately, several ways to answer the question. The information at the top of the screen gives the answer that the IRS is interested in: it shows figures based on the DATE THE MONEY ACTUALLY ARRIVED.
But another way of answering the question is to look at the dates of service that occurred last year, and see how much money EVENTUALLY ARRIVED for these dates of service. So the bottom part of the screen sorts the income based on the date of service, sorted by CPT code, instead of sorting it on the basis of the date the money actually hit your bank account.
As the cautionary statement on the report notes, these figures at the bottom of the screen can be distorted if you are looking at the recent past. You have to wait until all checks have come in for the service before the numbers are accurate.
So, to summarize: top of report = how much money came in last year
bottom of report = how much money did the work that I performed last year eventually earn for me.
Again, the IRS could care less about the bottom part. It is there so that you can learn how to allocate your time (doing what CPT codes) to produce the best income stream.