HMO insurance question

Sarah&royale

I have hmo through my work (healthnet) and also have hmo through my husband's job(blue shield) which I use as my secondary ins.  I called and found out that my ins. will cover 6 cycles of IUI (lifetime coverage) and basically finding out why we can't conceive (dianogstic.)  But they will only pay 50%.  So I called MH's ins to see if they would pick up the other 50% and nobody can give me a clear answer.  In the past, the only benefit I've had with having double coverage is that I never have to pay the usual co-pay.  IVF is not covered, unfortunately.  Any suggestions on what type of questions to ask the 2nd insurance.