I went through that on the preload. If >95% scans is that important, and you can't get a package off the belt, scanned and properly loaded without missing packages or causing a back-up/jam, then you gotta stack out. Don't go overboard but make a point of not putting anything into your trucks that hasn't been scanned yet.
A trick to that, though, you can scan a package, then hit the barcode inside the truck (the same one that you use to sort of sign in to your pull with your scanner) and drop what you've got on the floor. If the barcodes are in the back of your trucks then you don't even have to set foot inside for the scan to get logged and the package shown as on-car. Load it when you get a chance, and if you think you may not have scanned that one... * it, scan it again before you load it. Anything you don't have time to hit with a scan, leave it outside it's truck. Scan it when you can, toss it in the truck, load it when you get a chance. Just don't let it get to the point where you've got a pile of boxes so big you can't get in or around your trucks.