We just found out that the following formula delivers wrong results:
if ( [EINDEUTIGER MONAT] = MonthStart(today()),
if ( AUFTRAGSART='14',
if ( isnull(LIEF_NETTO_UMSATZ_VAHK),
if ( left(RECHNUNGSNR,2)='GS',
What this formula basically does is summarize RECH_NETTO_UMSATZ. The outer if-clause differs between the current month and all past months, the inner if-clause differs between different kinds of customers. So generally speaking, for all past months, the formula should be cut down to a simple sum (RECH_NETTO_UMSATZ), shoudn't it? Well, it doesn't.
If we simply use sum(XY) we get different results than if we use sum ( if (clause1 = FALSE,XY,0). We have no idea, why.