I never figured it out / I am not sure if Mori implemented it correctly. I never put much effort into it though. I know that the Tool Life counter is not working as the book says. The book explicitly say that when the life is up , cycle start is inhibited. It is most definitely not. I have tested it on several different Mapps controlled machines. The ones here at least.
I have seen programs here from my predecessor that have G313 in them. but I think you have to "teach" the acceptable load to use it. I know that just having a G313 and some other data words is not enough to keep from burning up a partoff tool, verified.
I use just some macro statements in the program to count tool usage by instance, preventing program execution if life count is reached.