Well, as is typical with this type of thing, I figured it out within 30 seconds of posting.
The addresses I was using via the mapping conversion were off by 1. I unchecked the zero based addressing in the device and the addresses mapped as expected.
To read MX100.1 does equal HR3050.1 now.
Hopefully thishelps someone in the future
***edit A response was made while I was typing my reply. I will try that also as I am learning how this PLC works with Ignition (and learning Ignition also)