I not like that script.. maybe you prefer other ways:
Some variation of that Dual Script:
The LTAP can switch the Dual SIM when the RSSI was weakness? - MikroTik
LED SIGNAL per RSRP
Better way to react at not working connection:
Simple watchdog: http://forum.mikrotik.com/t/sxt-lte-4g-cat6/134468/1
Advance watchdog: http://forum.mikrotik.com/t/tx-rx-fp-rx-dropped-pppoe-account/132656/1
Watch LTE parameters: http://forum.mikrotik.com/t/r11e-lte6-2ca-not-staying-connected/136004/22