Simple Equation Needing help

[sliderslider]

Dim preyearA As Double
Dim curryearA As Double
Dim MBB As Integer
Dim DGB As Integer
Dim success As Boolean

Success = Double.TryParse(txtPreYearMainBase.Text, Globalization.NumberStyles.Currency, CInfo, prevmainbase)
Success = Double.TryParse(txtCurrYearMainBase.Text, Globalization.NumberStyles.Currency, CInfo, currmainbase)
Success = Integer.TryParse(txtMBB.Text, MBB)
Success = Integer.TryParse(txtDollarGrowthB.Text, DGB)

If CInt(txtCurrYearMainBase.Text) > 0 Then
            Sum = (currmainbase - prevmainbase)
            If Sum >= 0.0 AndAlso Sum <= 99998.0 Then
                Sum = 0
                'Add some number of points.
            ElseIf Sum >= 99999.0 AndAlso Sum <= 149998.0 Then
                Sum = 2
                'Add some other number of points
            ElseIf Sum >= 149999.0 AndAlso Sum <= 199998.0 Then
                Sum = 4
                'Add some other number of points
            ElseIf Sum >= 199999.0 AndAlso Sum <= 249998.0 Then
                Sum = 6
                'Add some other number of points
            ElseIf Sum >= 249999.0 AndAlso Sum <= 299998.0 Then
                Sum = 8
                'Add some other number of points
            ElseIf Sum >= 299999.0 AndAlso Sum <= 10000000.0 Then
                Sum = 10.0
                'Add some other number of points
                txtDollarGrowthB.text = Sum.ToString
            End If
        End If


If CInt(txtCurrYearMainBase.Text) > 0 Then
            Sum = ((currmainbase - prevmainbase) / (prevmainbase))
            If Sum >= 0.0 AndAlso Sum <= 0.178 Then
                Sum = 0
                'Add some number of points.
            ElseIf Sum >= 0.179 AndAlso Sum <= 0.188 Then
                Sum = 3
                'Add some other number of points
            ElseIf Sum >= 0.189 AndAlso Sum <= 0.198 Then
                Sum = 4
                'Add some other number of points
            ElseIf Sum >= 0.199 AndAlso Sum <= 0.208 Then
                Sum = 5
                'Add some other number of points
            ElseIf Sum >= 0.209 AndAlso Sum <= 0.218 Then
                Sum = 6
                'Add some other number of points
            ElseIf Sum >= 0.219 AndAlso Sum <= 0.228 Then
                Sum = 7
                'Add some other number of points
            ElseIf Sum >= 0.229 AndAlso Sum <= 0.238 Then
                Sum = 8
                'Add some other number of points
            ElseIf Sum >= 0.239 AndAlso Sum <= 0.248 Then
                Sum = 9
                'Add some other number of points
            ElseIf Sum >= 0.249 AndAlso Sum <= 1.0 Then
                Sum = 10
                'Add some other number of points
                 txtMBB.Text = Sum.ToString
            End If
        End If

Basically I have another IF Then Ladder that is very similar to the examples above that works great. I just can't seem to figure out what has gone wrong with this piece of code as its more intuitive and should be easier. If I remove the Ladder (on the subtraction equation) and generate the answer it works but doesn't seem to go through the ladder.

As a note the numbers going into all the textboxes will be whole numbers.
And another note this is a clip from the code.

Thanks for your time