Why does my measurement takes the average of a value instead of aggregating?

[Tryg2015]

Hi Community

Can anyone help explain why my measurement takes the average of a value instead of aggregating?

I conducted a measure where I divided 2 column with formular:

= divide(sum(column1) , sum(column2), blank())

When selecting “Modeling” on the overhead, Power BI does not give me the option to choose “default summarization”.

Is it because of division that Power BI is unable to aggregate? Because when I just simply add the 2 column Power Bi is able to aggregate.

Thanks in advance