65% HF beads reading 70%???

I know yet another bead thread, but this is a strange one. I have 2 ounces of 65% HF beads in my 100 ct desktop humidor that I seasoned for a week (see thread) and both of my digitals (both recently calibrated with boveda calibration kit) are reading between 69-70% I used the formula to see if I'm using enough beads and according to my humidor dimensions, 2 OZ. is plenty.

In my 54 ct. coolidor with four cedar trays, and 5-6 boxes of sticks, I am using the remaining 14 oz. of beads in a dish and my digital is reading 65%. I swapped out digital hygrometers just to see if there was a difference, and the desktop digital (from my cooler) ended up going up to 70%, and the digital in my desktop (that I moved to my cooler) ended up going down to 65%. It's my understanding that adding more than enough beads won't increase RH but will only improve the overall efficiency of said beads...........so what gives? How is it possible that 65% beads are holding RH in a seasoned humidor half full of sticks at 70%?

http://www.cigarasylum.com/vb/showthread.php?t=42972