Safe Ride 4 Kids review for PreOrder Now Backorder WOD

This app is working better than another pre-sale app I tried (which oversold the number I had set). The customer service was helpful in getting WOD set up and working on my site. My only complaint is some orders are coming in without being tagged and apparently the customer is unaware it was on backorder. I noticed a slight delay in the button changing to "Backorder" and the shipping date showing up so I don't know if these customers are just super fast in hitting that "add to cart" button or if something else is causing the "backorder" to not be triggered. Perhaps it's a setting on that person's browser?