As far as I am concerned, you husband still is a solid Zero on his PSA, and has nothing to worry about.
If it were up to me, I don't think anything should be reported lower than <.1, anything else causes needless worry and fear, something us PC people already have enough of.
Even my first one spooked me. It was .05. I was disapointed that it wasn't a .01, or as some show, .001. My doctor said it was real good, and it is good. So now, when I do my next one in May, it is .06, I will be paranoid that I am doomed for reaccurance.
David in SC
Age 56, 56 at DX, PSA 7/7 5.8, 7/8 12.3,9/8 14.5
3rd Biopsy Sept 08: Positive 7 of 7 cores, 40-90%, Gleason 7, 4+3
Open RP surgery 11/14/8, Right nerves spared, 4 days hospital, staples out 11/24/8, 5th cath out on 1/19/9
Post-surgery Pathlogy Report:Gleason 3+4=7, pT2c, 42 grm, tumor 20%, Contained in capsular, clear margins, clear lymph nodes
First PSA Post Surgery 2/9 .05, 6 month on 5/9