DMN / Camunda Modeller: how to define a Parallel Multi Instance Result

(also asked here: Stackoverflow)

I want to include a decision table in my process.

As the input is a list of elements, I want to call it for each element in parallel.

When I look at the output it only includes one entry. So it seems that each execution overrides the previous one. Example: [{pricePerProcessInstance=150.0, pricePerTask=0.0}]

I suspect I do something wrong in the definition.

Here is the definition for it: