Power BI - Extrapolate average monthly expenses to remaining months of the year

Question

I am trying to find a solution for the following problem and I do not have that much experience yet with Power BI. Therefore the help of this community would be much appreciated!

I want to use the monthly average of expenses for current year and extrapolate that value for the remaining months of the year.

On top of that I would like to have the possibility to multiply the extrapolated value for the months of may and nov with a value such as 1.1.

So if available expenses are available up to February, the extrapolated outcome should look like this:

Month Expense amount Multiply value

jan 10
feb 6
mrt 8
apr 8
may 8.8 1.1

jun 8
jul 8
sep 8
oct 8
nov 8.4 1.05

dec 8

Thanks in advance for thinking along with me!

Best,

Yoran