Ther is a function to switch SIM cards automatically on certain data limit, you can find it in:
Network > WAN > MOB1S1A1 (or MOB1S2A1) > SIM Switch:
Enable automatic switching and On Data Limit
Further down there is a section for Data Limit configuration
Set desired cap and save.
In further releases you should be able to set the exact date to clear data counters, but unfortunately, there's no such function right now.