IME, exactly what you are asking for cannot be achieved with number formatting alone. If you can tolerate the decimal point being displayed with integers (25. instead of 25), then the same number format using # or ? as the placeholder instead of 0 will work: .Numberformat="#.##" or .NumeberFormat="?.??"

If you cannot tolerate seeing the decimal point with integers, then you will need conditional formatting or a block If to choose the number formatting based on a test of whether the cell contains an integer or not. Something like (using VBA to test the condition and choose the number format):
Set mycell=Range...
If Int(mycell.Value)=mycell.value then
mycell.NumberFormat="0"
Else
mycell.NumberFormat="0.##"
End If
help file explaining the meaning of placeholders in number format codes: https://support.microsoft.com/en-us/...rs=en-us&ad=us
help file for conditional formatting (see the section on using a formula to choose how to format cells): https://support.microsoft.com/en-us/...b-f1951ff89d7f

Does that help?