Just because you can hear gas escaping, that doesn't mean you have 11" WC at the end of that hose. Did you replace the regulator because of a failure, or was it simply an upgrade because it was time to do it? If you have the same symptom using either tank, the only item common to everything is the regulator, and they have been known to be defective out of the box.
2013 F250 XLT
I now have a Keystone Outback, but I try to help when I can.
Bitter Gun Owner