Customize ActiveX SpinButton Value - Not Decrementing (or Incrementing) Correctly

I have an Active X SpinButton control directly on a spreadsheet that changes the input cell. (The idea is that later on, there'll be a bunch of these input cells, accompanied by their respective SpinButton controls).

I'm allowing the user to define the Min, Max, and Step (SmallChange) value of the SpinButton because (1) I need it to do decimal points and negative numbers and (2) that's what my boss would have wanted.

So I set the Min, Max, SmallChange value in the SpinButton properties to "0" then try to manipulate them in the VBA code.

What went wrong with the code is hard to explain. But basically, when I use the SpinButton to increment or decrement, it didn't quite do it correctly. If I fix the increment part of code, then the decrement part of the code goes wrong and vice versa.

An example: I have Min as "0.5%" in cell B7; Max as "4.5%" in cell B8; and Step (SmallChange) as "0.5%" in cell B9. The Input cell is in cell B10 where user can either type in a value within the defined range (enforced by data validation) or use the SpinButton to change the value.

To replicate the problem: I type in "1.0" in the Input cell and click on the left SpinButton and it would not allow me to go to the defined lower limit (which is 0.5%) in this case.

Here are my codes:

Private Sub SpinButton1_SpinUp()

Dim MyMax As Variant
Dim MyStep As Variant
Dim MyInput As Variant

MyMax = SpinButton1.Max + Range("B8").Value
MyStep = SpinButton1.SmallChange + Range("B9").Value

MyInput = Range("B10").Value...................................