1. Have you owned the RV since NEW?
2. If so, was this a continued problem since NEW or just started recently?
3. Newmar DOES NOT go "cheap" when they spec out a RV and appliances.
If so, they would have HUNDREDS of upset customers, just not you.
4. One of your questions confused me about the M/W light. You connect to Shore Power and the GFCI's do not trip? But does the M/W light then pulsate? Or, you have not done the test?
5. Can you give a GOOD Multimeter read on the actual voltage when on Inverter? Not a wall plug in type meter.
6. Last, the BEST way to determine IF the Inverter may have a fault is to connect the Input and output 120 Romex wires together at the Inverter and then test both Shore and Genset. See if the GFCI's stay ON. THEN connect the Output back to the Inverter and see if the GFCI's trip when Inverter activated. If so, then you have a fault in the Inverter.
7. Make SURE the Grounding lug on the outside case of the Inverter is grounded to a chassis frame source.
8. You can go back with original MSW if cheaper, but a PSW is a better choice.
9. I would have him gurantee that if you replace either the PSW or the MSW, your problem will be fixed or you do not pay for the new Inverter. Doug
