916 fuel pressure problem

I have a brand new 916 installation (yes the one I had the Oil in exhaust problems with).  On the second successful run I noted that my fuel pressure was reading slightly beyond the acceptable range at 49psi but steady.   Max acceptable according to Rotax is 46psi except for momentary (3 second spike) to 50 psi.

This was with both Rotax pumps on and a feeder facet pump also running.  I have not fitted the wings yet, so the Facet pump was sucking up from, and returning to a fuel container.

I ran some additional tests without the engine running.  

• both feeder & both main pumps - 48.5 psi (I'd guess lower than 49 because only running off battery power)
• 1 feeder & both main pumps -48.5 psi (1or 2 feeder pumps makes no difference)
• 1 feeder & one (either) main pump – 46.5 psi ( I would expect this to be higher with engine running)
• I confirmed that the airbox to sensor was clear
• I popped the fuel regulator out and confirmed no debris
• I broke the circuit at "D" in diagram and fed the engine side into a container and capped the Header Tank side.  I ran the one main pump and had fuel flowing from D and pressure was 46.5 with one main pump.  This eliminates back pressure in the Header tank as a cause.

I'm using a N1EU07D (K in diagram) connected to the fuel line in circuit and also connected to the airbox.  

The letters referred to in the diagram are those in green.   

I've the newer (exposed) Rotax pumps. 

One item which is not standard is the check valve (E ) around the fine fuel filter.  I’ve temporarily installed a valve of lower breaking pressure in reverse direction here because I don’t have the correct one yet.  I don’t believe this could in any ways affect the results though.

I asked Rotax dealer about this and he just pointed me back to the table of pressures in the 916 install manual.

Have others ever seen consistent but slightly too high fuel pressure?