exhaust pressure reading high

[r_jacksondiesel]

While I was installing an Edge programmer today I took a look at the exhaust back pressure and it was reading 45 psi at idel. I shut the truck off and it still read 42 psi (absolute). What would the consequence be of the reading being high? I priced out a sensor and they are damn expensive, $260!! Anyone know a place that sells these for a fair price? Does it even matter? I don't seem to have any issue with the exhaust back pressure valve staying closed since it's high even when the engine is off.

Edit: I just realized I put this in the wrong section. Feel free to delete.