Filtering flowfields

Hi,

In Table 112 (Sales Invoice Header)  I made the next flowfields:

Prepayment Cr.Memo No.  CalcFormula: Lookup("Sales Cr.Memo Header".No. WHERE (Prepayment Order No.=FIELD(Prepayment Order No.),Prepayment Credit Memo=CONST(Yes)))

CLE Entry No.                       CalcFormula: Lookup("Cust. Ledger Entry"."Entry No." WHERE (Document No.=FIELD(No.)))

Remaining Amount             CalcFormula: Sum("Detailed Cust. Ledg. Entry".Amount WHERE (Cust. Ledger Entry No.=FIELD(CLE Entry No.)))

On Page 143 (Posted Sales Invoices) I put out these fields, and they show the correct values.

I would like to set filters for them. For "Prepayment Cr.Memo No." and "CLE Entry No."  fields, it works. But for the "Remaining Amount" field it doesn't.

E.g. I would like to filter those invoices, where "Remaining Amount" is bigger than 0. And it shows nothing, despite having invoices with that values.

Has anyone any idea, what the problem can be?

Thanks in advance,

Frida