Should we set a hardcoded time range to void tickets?

You should have flexible logic by reading the delay information from the ticket. Our risk management can set a larger delay (10, 15, or even more seconds) for some punters while monitoring them for possible irregularities. Therefore, hardcoding a set time for an expected response is not a good idea. Only if you do not get a response from the OTS system in the bet delay + 5 seconds should the ticket be voided.