When I select a single segment it shows A at one end and B at the other. Editing the speeds for each direction on that one segment works correctly. Many roads have some segments facing the opposite direction, and when selecting multiple segments this causes a glitch in the speed limit editing - since it's only editing one direction at a time and the software isn't correctly handling the mismatch of directions. It takes a third selection and typing of the new speed to overcome this glitch, which then shows as 3 changes instead of 2.

The A-B direction is presumably dependent on how the original editor drew the road, and is unimportant for most purposes. It would be useful to be able to have a button to just swap the B-A to A-B when a single segment is selected - without altering any of the other properties of that segment.