Hi Marius
On your planning strategy the planning indicator is "net requirements planning" instead of "single item planning". Therefore, the PIRs are obviously created as MTS. Please observe that any customizing change on the planning strategy may affect the PIR consumption and reduction, therefore, I do not recommend this kind of change.
I suggest you to get back the planning indicator to the original value (according to the screenshot from my system) and try again.
BR
Caetano