Low oil pressure at idle?

5.7 hemi idle psi is 10 roughly at temp. Goes up to mid forties on throttle. Haven't checked at WOT. Tried putting Rotella in just see if it gained pressure but did not change. Did some reading ,and some people have a low as 6 at idle,and as high as 40+. Question is should I worry,and should I put the 5w20 back in. It did tick on the top end after idling for 20 min with the 5w20 I m it