Partial scoring available with question pools?

Hallo, 

got a problem with partial points. Maybe you could help me ?

I created a gft file with two questions (multiple choice).

Each questions got four answer opportunities - two of them a correct and two are false.

For every correct answer the user should give one point, for every false answer the user should get no point. So in general, you can achieve four points! To pass the user needs at least two points. 

I uploaded the gft file directly into my question pool and created two slide of random questions out of the pool. However, the tests revealed that I had to answer the question completely correctly to get full points. As soon as I gave one correct and one incorrect answer, i didn't get any point out of the question

Why are the points not spread when I work with the question pool?

I also tried this Solution but without success. Please find attached the gft file.

What i'm doing wrong ?