How to get LTE uptime?

Hi, beginner here.

i just bought a Mikrotik SXT LTE Antenna to get some LTE signal in my rural area which have two telecom signals, A and B where i want the antenna to switch between whatever is available but always prefer A. To be able to do this i found a script in the Mikrotik wiki where it changes to the other telecom signal if the actual signal is down but that’s not all.

If the actual signal is B and B have been running for a while (like 60 min) i want the antenna to switch to A but i have not been able to read how long B have been running in order to trigger the switch. Here is the script that i want to run in the schedule.

#Check if simSlot=“B”
if (simSlot “B”) do={
#Check current time up, if>60 then switch the sim slot
:if ($LTEUPTIME > 60) do={
:log info message= " B Uptime out, switching slot to A
/system routerboard modem set sim-slot=a
}
}
Now, the closer i have been able to get the LTE uptime is by reading /interface lte info lte1 where i get what is in the image. Is there a way to get only the lte1 uptime? Is this a good approach to the problem?
lt1 info.png

To get the uptime value just use:

:local uptime ([/interface lte info [find name=lte1] once as-value]->"session-uptime")