Steve - Take a look at the pictures in my gallery under IAT Gauge. I just installed my IAT Gauge and noticed the same thing.

It looks like your coolant temps may read a bit lower then the intake air temps. We will need to do some more comparison.

When driving around town (stop and go) the IAT were 35 - 45 Deg above the OAT. - They would jump when at a stop and take a bit longer to cool down once moving.

When cruzing on the freeway - 65 to 75 MPH the IAT's were pretty constant at 25 - 35 Deg above the OAT. I thought they would be much higher.

I hit a 5-6 mile climb from 600' altitude to 3,700 and was on it - keeping the boot gauge at 12-16 lbs as best I could with the traffic and the IAT rose to 135Deg - that was the max reading I saw. But one off the boost and just cruzing - temps dropped right back down.