Thank you for the assistance.
Here my formula

IF {@Ddebut} in {lv_cr_76x.ddebut} to {@FinAccord} Then True ELSE False

I cannot guess in advance the value of @Ddebut.
If @Ddebut is not included between {lv_cr_76x.ddebut} AND {@FinAccord} the formula MUST turn over false.
It is not currently the case IN CR.

bernhart