Sub Sort()
Dim shNm1 As String, r1 As Long, c1 As Long
Dim shNm2 As String, r2 As Long, c2 As Long
Dim r As Long, c As Long, rEnd2 As Long, d, dd

shNm1 = "Лист1": r1 = 3: c1 = 12
shNm2 = "Лист2": r2 = 2: c2 = 10
c = c2: r = r1

rEnd2 = Sheets("Лист2").Cells(Rows.Count, 8).End(xlUp).Offset(1, 0).Row  'последняя строка любая с самого конца

Set d = CreateObject("Scripting.Dictionary")
Do Until Sheets(shNm2).Cells(r2, c) = ""
  d(Sheets(shNm2).Cells(r2, c).Value) _
    = Sheets(shNm2).Range(Cells(r2, c).Address & ":" & Cells(rEnd2, c).Address).Value
  c = c + 1
Loop
c = c2
Do Until Sheets(shNm1).Cells(r, c1) = ""
  If Not IsEmpty(d(Sheets(shNm1).Cells(r, c1).Value)) Then
    Sheets(shNm2).Range(Cells(r2, c).Address & ":" & Cells(rEnd2, c).Address) _
      = d(Sheets(shNm1).Cells(r, c1).Value)
  End If
  d.Remove (Sheets(shNm1).Cells(r, c1).Value)
  r = r + 1
  c = c + 1
Loop
For Each k In d.keys
  Sheets(shNm2).Range(Cells(r2, c).Address & ":" & Cells(rEnd2, c).Address) = d(k)
  c = c + 1
Next
End Sub

Sub aaa()
Dim x, y, z, rng1 As Range, rng2 As Range, i As Long
x = Sheets("ПРОДАЖИ").Range("J1:AC1").Value
Set rng1 = Sheets("УЧЕТ").Range("N3")
Set rng1 = rng1.Resize(UBound(x, 2))
Set rng2 = rng1.Offset(, -1)
z = rng2.Value
ReDim y(1 To UBound(x, 2),  1 To 1)
For i = 1 To UBound(y)
  y(i, 1) = Val(z(i, 1)) - Val(x(1, i))
Next
rng1.Value = y
End Sub

    Dim X() As Variant
    X = Sheets("ПРОДАЖИ").Range("J1:AC1").Value
    For i = 1 To UBound(X, 2)
        Sheets("УЧЕТ").Range("N" & i + 2).Value = Val(Sheets("УЧЕТ").Range("M" & i + 2)) - Val(X(1, i))
    Next

Sub test()
Dim arr(), arr1, i&
With Sheets("ПРОДАЖИ")
    arr = .Range("J1:AC1").Value
    arr1 = Sheets("УЧЕТ").Range("m3").Resize(UBound(arr, 2))
    For i = LBound(arr1) To UBound(arr1)
        arr1(i, 1) = Val(arr(1, i)) - Val(arr1(i, 1))
    Next i
   .Range("n3").Resize(UBound(arr1)) = arr1
End With
End Sub