You might ask if they retest in six months if you're concerned.
I second that suggestion: six months.
Let's say you were to wait one year and the result came back, uh, 5.93. Wouldn't it be helpful to know whether at six months it was > or < that level, so you could tell whether the PSA was continuing to bounce or was now steadily trending up? It's a cheap, easy test. That would be my call.
BTW, be sure to keep using the same lab and the same protocol. I noticed some of your prior PSA results were carried out to one decimal place, others to two.