Suppose we are using resource group 1110, that is having 3 resources (1311, 1111,1115)
Actual: The estimation is based on resource group, and the scheduling is based on resource. Since the customer is using scheduling, they are getting Substitution Variance which is by design.
Expectation - When they are taking any resource from the above resource group, they should get Quantity variance.
LCS Link: Details for issue 719292 (dynamics.com)