I see.. I hadn't ever seen that happen, but you're bound to have spent a lot more time with the app than me, so I'll take your word for it In at least one iteration, the screen was capable of being dragged left/right as well as up/down, which I thought was a perfect way of seeing large numbers which were going off screen.. TBH, my favourite version of this app was the one where you'd simply select the unit you want to start with, enter an amount in a field immediately next to it and see the rest of the conversions populate. It was simple, direct, and totally intuitive once you'd found the unit you want.
I can definitely see the dilemma there. Still.. they are different units, so there should be some indication as to the particular standard they're representing.. Two ideas come to mind at the moment: 1 - display the full name of the selected units at the top of the screen.. possibly in a line above the results (ie: "From: Unit A | To: Unit B"). 2 - move to two columns rather than three.. the user chooses a Category first, and then gets to a screen with the "TO" and "FROM" columns.. obviously that's a step back to something resembling the 'standard' mode, but I've never needed to access more than a single Category per use of Gonvert, so maybe it doesn't matter much.. Again, this is me speaking as a fan of the old, so feel free to completely ignore my input here