Don't be too concerned about the PSA level - it's not a reliable measure of anything, as readings can vary so much, and be influenced by so many (largely irrelevant) factors. As a first test, you are either 'within normal limits', or not. It's the Gleason score and scans, leading to the TNM staging that really matter.
The only value of the test - other than the initial 'flag' - is in Changes in PSA, which can indicate that (for example) hormone therapy is doing its job. Later, a rising PSA can again act as a flag that something may be awry.