I remember in the university many years ago we had an exercise where we tinkered with electrical meters. The mechanical one did turn both ways depending on the direction if the power flow. But that was more of a side effect of how the device worked, not some design decision. The digital one from that time did measure positive usage in both directions. I am not sure whether this was design decision... We only tinkered with the mechanical one, but we did test the digital one in both directions.