As the predecessor or more accurate the parent of P3D, MS FSX of course possesses the same characteristics via changes from the Eight (8) Thresholds in Heights and Thicknesses as mentioned in the last two posts regarding cloud effects in P3D.
|Base Height 0 feet||Thickness 1 feet|
|Base Height 6,562 feet||Thickness 3,000 feet|
|Base Height 19,686 feet||Thickness 6,000 feet|
|Thickness 10,001 feet|
|Thickness 15,001 feet|
Since the Thickness Thresholds are not always ending at zero, adding an extra 1 feet to the Thickness values would ensure the transformation of the cloud properly.