I need some guidance on how to achieve scenario below.

 

Scenario:

 

If i am running the report from Jan 08- Dec 08

I have 2 Tenants, 1 submitted 6 months Turnover, and when we calculate the
Average TO per month, the total TO need to be divided by 6 months
whereas another Tenants submitted 12 months Turnover, the total TO need to
be divided by 12 months.

How can i achieve that results? Please advice me on the formula that I should use.

 

 

Thanks & Regards,
Elisha