Digital hygrometer accuracy check

[GTS21]

I'm in the process of gauging the accuracy of several of my digital hygrometers using the Boveda calibration kits obtained from Viper. These kits are pre-set to 75.5% By the way--great service Viper, thanks!! Currently being tested are the following 5 units:

1 Western III
4 Diamond Crowns

Results so far (these need to sit for at least another day, so things may change a bit)

Western III -- 72%
Diamond Crown-- 68%, 69&, 72%, 73%, 75%

So the majority are reading a little low. My understanding is that these kits are reusable (for 3 months), so I'll be testing a few more Diamond Crowns and 6 Radio Shack wireless units. I'll report back. In case anyone cares. LOL.