Te anexo el código completo de la función para agregar los datos.
Sub PegaDatosDeInteresesEnCashflow(f, filabono)
'Por.Dante Amor
Dim fec As Date
Set h1 = Sheets("INTERESES")
Set h2 = Sheets("CASHFLOW")
Set h3 = Sheets("BONOS")
u = 5
Do While h2.Cells(u, "A") <> ""
u = u + 1
Loop
h2.Rows(u + 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromRightOrBelow
h2.Cells(u, "A") = h1.Cells(f, "A")
h2.Cells(u, "B") = h1.Cells(f, "C") & " - COMPRA"
fec = DateSerial(Year(h1.Cells(f, "A")), Month(h1.Cells(f, "A")), 1)
Set b = h2.Rows(2).Find(fec, LookIn:=xlFormulas)
If Not b Is Nothing Then
h2.Cells(u, b.Column) = h3.Cells(filabono, "R") * -1
End If
u = u + 1
h2.Rows(u).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromRightOrBelow
For i = f To h1.Range("A" & Rows.Count).End(xlUp).Row
fec = DateSerial(Year(h1.Cells(i, "B")), Month(h1.Cells(i, "B")), 1)
Set b = h2.Rows(2).Find(fec, LookIn:=xlFormulas)
If Not b Is Nothing Then
h2.Cells(u, "A") = h1.Cells(i, "A")
h2.Cells(u, "B") = h1.Cells(i, "C") & " - INTERESES"
h2.Cells(u, b.Column) = h1.Cells(i, "D")
End If
Next
h2.Select
MsgBox "Datos archivado en el Cashflow", vbInformation
End Sub