i want to count time in particular state choice label inmaintaince | value is 3
I would suggest using Metrics to do this instead of a Business Rule. With Metrics Definitions [metric_definition] you can set the type to "Field value duration", and the field to whatever field you are looking at.
The results are found on the Metric [metric_instance] table.
It will save you a lot of time and frustration with the calculations.
Metric Definition
Metric
