This is just an opinion, but...

I use a LunaPro with adapter and the transition from merc batts to adapter was seamless. I suspect you may need to brush up on the instruction manual. I do not intend to be offensive in any way but if, on the Luna Pro, you are not taking the number indicated by the needle (Light Value) and transfering it to the calculator you are omitting the important impact of film speed on your exposure information.