Combining UDF with IF function

[AC2411]

I need to combine a UDF (below) with a set of IF functions.

Function MaxN(n&, r As Range)
Dim i&, j&, m#, t#, v
v = r.Cells.Value2
For i = 1 To UBound(v)
If UBound(v) - i + 1 >= n Then
t = 0
For j = i To i + n - 1
t = t + v(j, 1)
Next
If t > m Then m = t
Else
Exit For
End If
Next
MaxN = m
End Function

I'm trying to use this UDF (which finds the max value of 5 consecutive cells in a range) in combination with IF functions.

Eg: IF(A1=D1) and IF(B1=E1) then apply the UDf, otherwise leave blank (or = 0)

Appreciate the help!

 

[Crystalyzer]

=IF(AND(A1=D1,B1=E1),MAXN(1,A1:A5),0)

 

[AC2411]

=IF(AND(A1=D1,B1=E1),MAXN(1,A1:A5),0)

I've tried this formula, however it always returns zero (even if there are values there).

I'm trying to use the UDF on a large range of data IF it occurs on month (0-12) and year (2000-2017).

Basically my cells look like below, and I'm using the formula {=IF(AND($B$2:$B$427613=H2,$C$2:$C$427613=$F$3),maxn(5,$D$2:$D$427613),0)}