Looks like you're dead on for what I saw and what's expected if it's working right. My cold idle was 65psi and fully warmed up was in the low 20s.
I think you found that you have the same issue I have....the car's working properly but the sending unit isn't. Try the Echlin one and see what you come up with on the gauge. If not, pick up the more expensive Delco one.
http://jerrysgaskets.com/store2/root...roducts_id=106
Chris