How to make 'n/a' not contribute to the overall rating in competency section of performance document

Summary:

Hi,

My client would like to offer an 'N/A' option to the competency rating model in the performance document. This is due to the fact that the competency may not apply to the employee. As such, I would like to make this not contribute to the overall rating if 'N/A' is selected. I would like to use average as the rating needs to be out of 5 and not use the sum calculation.

Content (please ensure you mask any confidential information):

I have made N/A rating as '0' in the rating model and also tested it being blank, but it always contributes to reducing the overall average.