For some cases, they give slack timings instead of revision in halt timings from 5 to 15-20 mins.
You can take example of 06581 Hampi express special, Huge slack is provided between TNGL and BAY , Huge slack is there between this two station because of LC. Observe the official halt timings at BAY it is 5 mins, but it is detained for more mins for LC , but after departure from BAY, Slack gets adjusted with the TT.