I like the idea, but there are two things that jumps into my eyes:

1. It generates invoice - but for which country? While invoices look similar across countries, usually they have a strict minimal content, which can vary between places.

2. It's alpha software. Every software starts at alpha, that's a natural thing. But also I wouldn't trust my company on an alpha software to save a couple of hundred bucks. I wonder if the author has a company where he dogfoods it.