Recommendation About Maintenance Organization Costing.

Hi Team - Just to clarify, It is recommended that for Maintenance Org, we should create separate inv org than manufacturing org for maintenance activities and reason would be like if we need separate WO # or if we need a separate calendar for maintenance then creating a separate org would be helpful. On the similar note it is also recommend to use avg costing for the maintenance activities. So is there any reason for using Avg costing for maintenance org trxs?

Our client is using std cost for manufacturing activities, so just wanted to know what would be some advantages/disadvantages if we go with std costing for maintenance activities? And Why Avg Costing is recommended.?