Excel VBA - Flipping Numerical Sign - excel

Question

I have some code that copies data from one tab and pastes it into another tab then flips the numerical sign on an entire column. Example, -1 in original tab turns to 1 while 1 in original tab turns to -1.
For some reason, if the number in the original tab is a negative, it will not turn positive. If the number in the original tab is a positive, it will turn negative just fine. Any ideas of what might be causing this?
The last 3 lines of code is what ultimately flips the signs but I pasted my entire sub in case there's something elsewhere causing the issue. Thank you in advance!
Sub prep()
Dim c As Range
Dim IRow As Long, lastrow As Long
Dim rSource As Range
Dim wsI As Worksheet, wsO As Worksheet
Dim d As Range
Dim dSource As Range
Dim LR As Long
On Error GoTo Whoa
Set wsI = ThisWorkbook.Sheets("Ben")
Set wsO = ThisWorkbook.Sheets("Upload")
Application.ScreenUpdating = False
wsO.Range("P14", "AB10000").ClearContents
endrow = wsO.Cells(Rows.Count, "T").End(xlUp).Row + 1
With wsI
If Application.WorksheetFunction.CountA(.Cells) <> 0 Then
lastrow = .Columns("O:R").Find(What:="*", _
After:=.Range("O1"), _
Lookat:=xlPart, _
LookIn:=xlFormulas, _
SearchOrder:=xlByRows, _
SearchDirection:=xlPrevious, _
MatchCase:=False).Row
Else
lastrow = 1
End If
Set rSource = .Range("R1:R" & lastrow)
For Each c In rSource
Debug.Print c.Value
If IsNumeric(c.Value) Then
If c.Value > 0 Then
wsO.Cells(14 + IRow, 20).Resize(1, 4).Value = _
.Range("O" & c.Row & ":R" & c.Row).Value
wsO.Cells(14 + IRow, 25).Value = "XXXXXX" & .Range("J" & c.Row).Value
wsO.Cells(14 + IRow, 28).Value = .Range("N" & c.Row).Value
wsO.Cells(14 + IRow, 16).Value = "470"
wsO.Cells(14 + IRow, 17).Value = "I"
wsO.Cells(14 + IRow, 18).Value = "80"
wsO.Cells(14 + IRow, 19).Value = "A"
IRow = IRow + 1
End If
End If
Next
End With
For Each r In Range("W14", Range("W" & Rows.Count).End(xlUp))
r.Value = -r.Value
Next r