Sum in drill down feature does not work with IF statement

[chinh_ho]

 Good morning, everyone. 
I am a newbie to Power BI, and I have a question about the drill down feature in matrix. I really appreciate your help.
I have a matrix which drill down to multiple lower level. In my measure, I want it does not show up lower value in What-IF Pamameter. I was able to do it, but when I drill down to lower level, it does not sum up correctly. 
Please refer to the picture.

The left measure sum up does not correct because I use: IF([measure1]<WHAT-IF Parameter, Blank(), [measure2])
The right measure sum up correct because I did not use any If statement.
Can anyone please help me to solve the problem for the total in the left measure to match when we drill down to lower level.
Thank you so much.