Fixed vendor, Pgroup and Porg not defaulted in Preq generated from MRP

hello all.

after checking all the forums and all the given solutions, I still have this problem.

MRP generates a Preq for a material but data, namely Pgr, Porg, Fixed vendor, is not defaulted.

prerequisites fulfilled:

1) PIR is created with vendor, material, Porg

2) material has sourcing obligatory

3) source list is created with Porg and with valid dates: vendor is marked as fixed and MRP is marked as 1

4) material and PIR contain Pgr

5) "source determination" box is checked in default values of Preq

6) if I click on button "Assign source of supply" in Preq, the vendor with its info record appears but Pgr is still being requested.(and I would like the data to appear automatically, not manually)

7) other materials of same type work fine and Preq generated defaults the values.

is there any other setting I maybe have overseen? any idea?