My 3 grandkids all call me Grandma, but their other grandmas are GaGa, MeMaw, and Nana.

Congrats to Kempo - you will LOVE being a Grandpa!!!!
Now back to the Infinity
batteries, and my main reason for posting:
I've been checking voltages for all my
batteries for about a month now, as the Gray Ultrafires for my original Buzzes (about 1 year 4 mos old) are declining & I wanted to keep an eye on them. HOWEVER, the Infinity batts are the ones that have me puzzled.
My original Infinity was ordered 1 year ago today, so the batts are about that old & I use the charger that Mike sells with these. I alternate 2 sets of batts, switching them out every morning. I unplug the charger soon after the lights indicate the batts are charged and so when I measure the off charger voltage, they have been off the charger almost a day. Hope that's enough background, lol.
Off the charger, I'm getting voltages (for the Infinity batts) at 4.23, 4.22, 4.24 - never under 4.20. My Powerizer batts (used on BP) have on a few rare occasions been at 4.21, but usually in the 4.17 - 4.19 range. So 1st question is if this is normal or something to be concerned about?
2nd question concerns the ending voltage. Last week, on 1 set of Infinity batts the end voltage was 3.66 and 0.00. I couldn't get a reading on that 1 cell no matter what I did, and so I disposed of that set choosing to err on the side of caution. Now a similar thing happened this morning with a different set. End voltage readings were 3.46 and 0.00. I don't want to put these back on the charger if it will be unsafe & so advise me here please.