Yeah, I guess that would be the most important part (80/20 rule). The admin interface is more or less responsive, I can live with the bit scrambled interface when I'm on mobile occasionally. But I think you are coming up with a mobile app for the back office aren't you?
Indeed the mobile view could be a lot better. It's a tricky thing to do as there are lots of parts to the invoice. We've ignored mobile a bit as there was a lot of hype around it but we weren't seeing the mbl traffic. The mbl traffic has increased, but were looking to jump the traditional mobile strategy and go for more a chat style interface, bot type thing. We've started working on that over 6mts ago with Dev starting 6 weeks ago. We hope to have a V1 in the next month or two. We've got a alpha stripped version ready for android. I know that doesn't answer your question but basically we're looking to build something for 5yrs time now 5wks.