In reply to Gordon Robb:
Just about to do a session or two on mine.
I think that's probably a graphics thing on the app.
My advice is to use the big jug as open handed as you can until you can treat it like a sloper.
Takes some time but ultimately very rewarding. It's also worth being circumspect with the other holds to avoid injury. I've been using one for some time, but never use crimps or chisels, always open handed. It's a great thing if it transfers into your general climbing
Hope it goes ok