I contacted Aeotech support for help and it’s now working as I’d have hoped.
This is the support they provided for anyone else hoping to do the same:
So you are running into a wall with battery powered MultiSensor 6 units, these units are designed to try to conserve battery power in this case so Parameter 111-113, and the threshold checks are restricted to the wakeup interval of the MultiSensor 6.
By adjusting faster report times, you will consume much more battery power (like 2 month battery life with 300 second reports).
But if you want the 300 second reports to run you must do this:
1. Expand Wakeup section
2. Set Wakeup Interval to 300 (this will set the minimum setting of Parameter 111 = 300 and should allow for 5 minute reports).
I would also recommend disabling sensors that you do not use such as UV and BATTERY on Parameter 101.
Set Parameter 102 to BATTERY and leave Parameter 112 to 3600.