UPS Shutdown after 5 min

hello,

we tested our UPS last week and it shutdown after accurately 5min.

I've searched around but find no setting.

i can see that "Shutdown duration" = 120 sec and "Shutdown if remaining tim under" = 180

and that will be 300sec but in the logfile the entry told me "shutdown in 18 mn 20s"

please help

Tibor