Touch.X uses a different unit?

Whenever the player starts a touch, I set the TouchStartX value by using Touch.X

However, comparing this to the Touch object's data shows that they don't have the same values. It says the X position is much less than the TouchStartX, and it also doesn't account for the viewport scrolling.

Does the Touch object use a different measurement unit than Touch.X?

That may be a coordinate from a different layer. Try using Touch.X(layer) expression.