Apply customs handling time at a airport location

Summary:

We have a requirement to apply the customs time that is required at the airport location.
The shipment leg transport mode is of AIR and has air-schedule rate service.

We tried to define the handling time on the Location role profile level. But we want it airport location specific and not for all airports. Even if applied, this handling time does not get reflected on the start and end time of shipments, using default OTM function.

Secondary charge shipments can be created- specifying the secondary charge rule and cost details for that custom broker. But this secondary charge shipments start and end times need to be in synch with the shipments from other legs, which does not happen using OTM default workflow.