See if this works
Sub CreateSheets()
Dim WBO As Workbook
Dim ThisWS
Dim rngFilter As Range 'filter range
Dim rngUniques As Range 'Unique Range
Dim cell As Range
Dim counter As Integer
Dim rngResults As Range 'filter range
Dim LastRow As Long
Dim Values As Range
Dim iX As Integer
Dim savedValue As Variant
Set WBO = ThisWorkbook
Set rngFilter = Range("O4", Range("O" & Rows.Count).End(xlUp))
Set rngResults = Range("A1", Range("N" & Rows.Count).End(xlUp))
Set rngformula = Range("C5", Range("N" & Rows.Count).End(xlUp))
With rngFilter
.AdvancedFilter Action:=xlFilterInPlace, Unique:=True
Set rngUniques = Range("O5", Range("O" & Rows.Count).End(xlUp)).SpecialCells(xlCellTypeVisible)
End With
For Each cell In rngUniques
Worksheets.Add After:=Worksheets(Worksheets.Count)
ThisWS = cell.Value
ActiveSheet.Name = ThisWS
'counter = counter + 1
rngFilter.AutoFilter Field:=1, Criteria1:=cell.Value
rngResults.SpecialCells(xlCellTypeVisible).Copy Destination:=WBO.Sheets(ThisWS).Range("A1")
LastRow = Cells(Rows.Count, "B").End(xlUp).Row
If LastRow >= StartRow Then
With Range("B5:N" & LastRow)
.Sort Key1:=.Cells(1, 1), Order1:=xlAscending, Key2:=.Cells(1, 2), order2:=xlAscending
End With
With Range("C5:N" & LastRow)
savedValue = Range("A1").Value
Range("A1").Value = -1
Range("A1").Copy
.PasteSpecial Paste:=xlPasteAll, Operation:=xlMultiply
Range("A1").Value = 100
Range("A1").Copy
.PasteSpecial Paste:=xlPasteAll, Operation:=xlAdd
Range("A1").Value = savedValue
End With
End If
Columns("B:N").AutoFit
Next cell
End Sub