Just saw this post in reddit that I believe is a solid idea when it comes to using the arrow keys and inputting your dimension amount:
This was in reply to someone showing the tool in ZZT.
I can see how this would be nice. But if you make it assume the last 2 digits are inches, then you'd no longer have the ability to enter more than 99 inches.
And some users like to work strictly in inches. So changing this may help some but hinder others.
Good point. Maybe making it strictly inches would solve it, but not something high on the priority list. If we were to think through some use case scenarios and optimize it was the more the idea.