Tablature stem direction
In books by Publisher (or software) 1, the tablature is downstem for single voice (see Electric Guitar 2).
If there's multi-voice, the Voice 1 notes are upstem and Voice 2 are downstem (see Electric Guitar 3).
Looking at Publisher 2 (probably using different software), the direction is either up or down.
I wonder if it was a conscious decision for Publisher 1 (or the software) to always place single voice in one stem direction for easier reading.