Based on different companies workflows, an SO may not always be relevant. Our company in particular goes straight to invoice as paid because we receive payment at the same time as our orders are placed by customers. 

I love the fact that we can go from SO to PO, but I think it would be amazing if we could have the same function from invoice. This would save on duplicate entry work, prevent issues from having to manually carry over the information and just create a more seamless system.