Personally I think you’re artificially limiting yourself by not making this a web application. For inventory management, I wouldn’t want to be tied to an app that I can only use on a tiny mobile screen.
You have a good point on no web app and you're not the first to ask. I imagine at some point I will get there, but I didn't want to try to do too much at the start. Dealing with inventory on tiny mobile screen is why I put effort into the tablet versions of the app as well.