diff --git a/monthly.bas b/monthly.bas
new file mode 100644
index 0000000..1b1b757
--- /dev/null
+++ b/monthly.bas
@@ -0,0 +1,118 @@
+Sub calc_mval()
+
+    Dim pchange As Double
+    
+    If IsNumeric(tbMFVal.value) Then
+        'calculate percent change
+        pchange = CDbl(tbMFVal.value) / (CDbl(tbMPAVal.value) + CDbl(tbMBaseVal.value))
+        
+        'plug the adjustment required
+        tbMAVal = Format(CDbl(tbMFVal.value) - CDbl(tbMBaseVal.value) - CDbl(tbMPAVal.value), "#,###")
+        
+        
+        '---------if volume adjustment method is selected, scale the volume up----------------------------------
+        If opmVol Then
+            tbMFVol = Format((CDbl(tbMPAVol.value) + CDbl(tbMBaseVol.value)) * pchange, "#,###")
+        Else
+            tbMFVol = Format((CDbl(tbMPAVol.value) + CDbl(tbMBaseVol.value)), "#,###")
+        End If
+        tbMFPrice = Format(CDbl(tbMFVal.value) / CDbl(tbMFVol.value), "#.000")
+        tbMAVol = Format(tbMFVol - (CDbl(tbMBaseVol) + CDbl(tbMPAVol)), "#,###")
+        tbMAPrice = Format(CDbl(tbMFVal.value) / CDbl(tbMFVol.value) - ((CDbl(tbMBaseVal.value) + CDbl(tbMPAVal.value)) / (CDbl(tbMBaseVol.value) + CDbl(tbMPAVol.value))), "#.000")
+    Else
+        'tbMFVal = Format(CDbl(tbMPAVal.value) + CDbl(tbMBaseVal.value), "#,###")
+        tbMAVol = Format((CDbl(tbMFVol.value) - CDbl(tbMBaseVol.value) - CDbl(tbMPAVol.value)), "#,###")
+        tbMAPrice = 0
+        'tbMAPrice = Format(CDbl(tbMFVal.value) / CDbl(tbMFVol.value) - ((tbMBaseVal + tbMPAVal) / (tbMBaseVol + tbMPAVol)), "#.000")
+    End If
+End Sub
+
+Sub calc_mprice()
+
+    If IsNumeric(tbMFPrice.value) And tbMFPrice.value <> 0 Then
+        tbMFVal = Format(CDbl(tbMFPrice.value) * CDbl(tbMFVol.value), "#,###")
+        tbMAVal = Format(CDbl(tbMFVal.value) - CDbl(tbMBaseVal.value) - CDbl(tbMPAVal.value), "#,###")
+        tbMAPrice = Format(CDbl(tbMFVal.value) / CDbl(tbMFVol.value) - ((CDbl(tbMBaseVal.value) + CDbl(tbMPAVal.value)) / (CDbl(tbMBaseVol.value) + CDbl(tbMPAVol.value))), "#.000")
+    Else
+        tbMFVal = 0
+        tbMAVal = Format(CDbl(tbMFVal.value) - CDbl(tbMBaseVal.value) - CDbl(tbMPAVal.value), "#,###")
+    End If
+    
+End Sub
+
+Sub calc_mvol()
+
+    Dim pchange As Double
+    
+    If IsNumeric(tbMFVol.value) And tbMFVol <> 0 Then
+        'price should already have been re-calculated to base + prior at this point
+        tbMFVal = Format(CDbl(tbMFPrice.value) * CDbl(tbMFVol.value))
+    
+        'calculate percent change
+        'pchange = CDbl(tbMFVal.value) / (CDbl(tbMPAVal.value) + CDbl(tbMBaseVal.value))
+        
+        'plug the adjustment required
+        tbMAVal = Format(CDbl(tbMFVal.value) - CDbl(tbMBaseVal.value) - CDbl(tbMPAVal.value), "#,###")
+        tbMAVol = Format(tbMFVol - (CDbl(tbMBaseVol) + CDbl(tbMPAVol)), "#,###")
+        tbMAPrice = Format(CDbl(tbMFVal.value) / CDbl(tbMFVol.value) - ((CDbl(tbMBaseVal.value) + CDbl(tbMPAVal.value)) / (CDbl(tbMBaseVol.value) + CDbl(tbMPAVol.value))), "#.000")
+    Else
+        tbMFVal = 0
+        tbMAVal = Format(CDbl(tbMFVal.value) - CDbl(tbMBaseVal.value) - CDbl(tbMPAVal.value), "#,###")
+        tbMAPrice = Format((tbMBaseVal + tbMPAVal) / (tbMBaseVol + tbMPAVol), "#.000")
+        tbMAVol = Format(-CDbl(tbMBaseVol.value) - CDbl(tbMPAVol.value), "#,###")
+    End If
+    tbMFVal = Format(tbMFVal, "#,###")
+
+End Sub
+
+
+
+Private Sub opEditPriceM_Click()
+    opmVol.Enabled = False
+    opmPrice.Enabled = False
+    opmVol.Visible = False
+    opmPrice.Visible = False
+    opmPrice.value = True
+    opmVol.value = False
+    
+    tbmfPrice.Enabled = True
+    tbmfPrice.BackColor = &H80000018
+    tbmfVal.Enabled = False
+    tbmfVal.BackColor = &H80000005
+    tbmfVol.Enabled = False
+    tbmfVol.BackColor = &H80000005
+    
+End Sub
+
+Private Sub opEditSalesM_Click()
+    opmVol.Enabled = True
+    opmPrice.Enabled = True
+    opmVol.Visible = True
+    opmPrice.Visible = True
+    
+    tbmfPrice.Enabled = False
+    tbmfPrice.BackColor = &H80000005
+    tbmfVal.Enabled = True
+    tbmfVal.BackColor = &H80000018
+    tbmfVol.Enabled = False
+    tbmfVol.BackColor = &H80000005
+    
+End Sub
+
+Private Sub opEditVolM_Click()
+    opmVol.Enabled = False
+    opmPrice.Enabled = False
+    opmPrice.value = False
+    opmVol.value = True
+    opmVol.Enabled = False
+    opmPrice.Enabled = False
+    opmVol.Visible = False
+    opmPrice.Visible = False
+    
+    tbmfPrice.Enabled = False
+    tbmfPrice.BackColor = &H80000005
+    tbmfVal.Enabled = False
+    tbmfVal.BackColor = &H80000005
+    tbmfVol.Enabled = True
+    tbmfVol.BackColor = &H80000018
+End Sub
\ No newline at end of file