Originally Posted by draver

I am on a grandfathered ONE plan. My ONE Plus Promo gives me almost exactly the same roaming features as MM. The voice lines I am using in iPads are a mix of paid & free. I have a spare paid voice line and 4 other free lines. We also have our 2 regular voice lines and all 7 of these get the free 5Gb HS data roaming. I also have 5 other family members on the account and they all get the roaming features.
Your phone should be able to display your data use, but you may need to record it's starting amount prior to a trip. Your On Line Account Manager might be helpful here also. That is where you should be able to find the upgrade for Netflix too.