Many years ago, I was on a full-and-standing Cross Country train. In the buffet car, naturally, as it was more pleasant to stand and drink beer leaning against a counter than to stand beerless in an aisle. Got talking to the guard, who was bemoaning not being able to meet his ticket sales targets, due to not being able to get through the train. So I asked him if a zero excess counted toward his target. Apparently, it did; so I got him to excess my ticket from Birmingham Stns to Bordesley. Maybe it's silly jokes like that that are partly to blame for reluctance these days.
Welcome to the forum, James ... shows the danger of setting up sales target systems!
Although it may count towards sales targets, it counts AGAINST the company if the zero excess causes another
TOC▸ to be involved as the original fare may have to be redistributed among more TOCs, thus losing money on the original sale. This also counts against commission and may also cause the person who has sold the ticket a stern talking to.