How to set Amount to Apply in Payment Allocation to invoice from code

Hi Guys
I thought it's simple to allocate payments to invoices from code but after couple of days of trying I need help..:)
Basically it works setting the Applied-To-Id and remaining amount , but always takes the remaining amount instead of the amount to apply
This is my simple codeunit

var
        CustLedgEntry: Record "Cust. Ledger Entry";
        ApplyingCustLedgEntry: Record "Cust. Ledger Entry";
        CustEntrySetApplID: Codeunit "Cust. Entry-SetAppl.ID";
    
        CustEntryApplyPostedEntries: Codeunit "CustEntry-Apply Posted Entries";

    begin

        CustLedgEntry.SetRange("Entry No.", 144);
        ApplyingCustLedgEntry.SetRange("Entry No.", 157);
        CustLedgEntry.Validate("Amount to Apply", -25);

        ApplyingCustLedgEntry.Validate("Applies-to ID", 'TEST1234');
        ApplyingCustLedgEntry.VALIDATE("Amount to Apply", 25);
        CustEntrySetApplID.SetApplId(CustLedgEntry, ApplyingCustLedgEntry, 'test1234');

        ApplyingCustLedgEntry.VALIDATE("Amount to Apply", 25);

        ApplyingCustLedgEntry.MODIFY(true);

        CustEntryApplyPostedEntries.Apply(ApplyingCustLedgEntry, ApplyingCustLedgEntry."Document No.", CustLedgEntry."Posting Date");

    end;

so far the only way to get amount to apply populated was changing the setappl.ID codeunit (creating my own) as below

if ((CustLedgerEntry."Amount to Apply" <> 0) and (CustEntryApplID = '')) or
           (CustEntryApplID = '')
        then
            CustLedgerEntry."Amount to Apply" := [b]ApplyingCustLedgerEntry."Amount to Apply" * -1[/b]//-1//original 0
        else
            if CustLedgerEntry."Amount to Apply" = 0 then begin
                CustLedgerEntry.CalcFields("Remaining Amount");
                CustLedgerEntry."Amount to Apply" := [b]ApplyingCustLedgerEntry."Amount to Apply" * -1[/b];//original CustLedgerEntry."Remaining Amount"
            end;

I still cannot use above since I need discounts, tolerance etc to be working and want to get see the best possible option. Looks like writing to ledger entries is quite complicated