If you know the sequence number ahead of time then you can attach any transaction to it, including two conflicting. The point of hardware counter is that you (

If you know the sequence number ahead of time then you can attach any transaction to it, including two conflicting. The point of hardware counter is that you (your device, actually) sings a counter along with a transaction. You couple them together in a way, that you can't counterfeit, because you can't tamper the device.