Does it drop to 9.5-9.3 and stay there or does it continue to drop over time?
Check to make sure your 2nd stage(s) cracking effort is set properly and not too high.
Check for leaks at any hose connections and the shrader valves in your power inflator hose.
Check your power inflator itself is not leaking.
Check the connection at your IP gauge.
If you are checking IP at the power inflator hose, perhaps check it at the end of a 2nd stage hose and see if it exhibits the same IP behavior.
The IP pressure range for your 2nd stage is 9.8Bar to 10.2Bar. Perhaps increase your IP slightly to see what affect it has on the situation.
Or, since it is a new service kit, the issue could be that the poppet seat in one or both of your 2nd stages is still breaking in....though I would be concerned that the drop in IP of nearly 8psi is not causing a free flow, so it could be a combination of the poppet seat not fully taking a set yet coupled with a cracking pressure set too high.
There is good info in the attached document that you may find useful. One check that is outlined in the checklist to pressurize your reg and leave it overnight to see if the tank pressure drops over time, indicating a slight leak.
Perhaps
rsingler has some insight that might be of help.
-Z
