Not sure what you're after here. Standard test results tolerance are
something like 0.05 (plus or minus). High resolution tests are
something like .002 (plus or minus), but PSA readings taken close
together can very all over the map, and that is normal.

If you have a good PSA testing history, PSA acceleration and PSA
doublilng data can be very useful since it is supports a more
qualitative analysis, and PSA testing's purpose is generally more
qualitative than quantitative. Get your specific numbers from a  DRE
and biopsy (stage and Gleason) if the PSA qualitative results point
that way.

Hope this helps. I'm sure that many more of us will chime in!