Coming from the slash side of fandom for me "AxB" is a defined Seme x Uke relationship, whereas "A/B" is an interchangeable relationship. Both indications without meaning in regard of dominance. I was pretty mindboogled when I stumbled into shonen ai and yaoi. Nowadays all the pairing indications are pretty wishy-washy and not as strict as they used to be ten years or so ago.