Variance between Default and Last Year on multiple measures

[RobinvL]

I have a dataset that I can use for a company.  I made a matrix visual, like below. 
In the rows, there is an option to drill down to a daily level.

There are relative periods, default is for the selected period. Last Year refers to the same period last year. This information is already in the dataset.
I want to have a "Third" column where I display the difference between Default and Last Year.

I already tried a solution where I made new measures for each measure where I calculate the difference, but when drilling down PowerBi gave a message that it's low on memory.