Finally solved with Note 32900
It seems that activation of BADI CNIF_MAT_UPDATE is not necessary when implementing corrections of OSS note 32900.
Plus: with note 32900, quota are considered in automatic source determination in CJ20N.
The only remanent thing is that when changing something in an already created component, it doesn't recalculate the good PIR; and when changing source in ME52N, source is not changed in CJ20N.
Claire.