When you implement SLA feature in CRM 2015/2016 you might worry about these fields as they would be filled only based on the SLA type – ‘Standard’. You may remove the fields from the Case form depends on the SLA type (‘Enhanced’) you opt for the CRM setup.
If you enable the standard SLA, the below fields would be populated with values:
If you enable Enhanced SLA, then the below fields would not be populated.
Instead, Enhanced SLA values would be populated in this case – together with the Timer function.