Check If Condition Is Met

Private Sub cmdNext_Click()
' Save form contents before changing rows:
SaveRow
' check that it is not the last row - if it is then show message
' and do not go to next record:
If Sheets("Data"). Cells(lCurrentRow, 1).Value = "" Then
MsgBox "This is the last Output."
lCurrentRow = lCurrentRow - 1
Exit Sub ' Abort if no data:
Else
LoadRow
End If...................

I'm having trouble with is the bit where it is supposed to ask for the txtAddInfo to be filled (if blank) and if the txtdifference is greater than 10% or less than -10%. It seems to work fine if the txtDifference is less than -10% but not if the txtDifference is greater than 10%. It just seems to get stuck, the message box is displayed even if txtAddInfo has infomation within it.

I'm not sure why as I use ..........