Parallax Scrolling Texture's Height Problem

Hello there! I am trying to set up a simple 2D parallax scrolling for my SideScroller game and it seems i have a problem with texture’s height.

So basically, I am trying to split the layers of textures from one another using a Bump Offset and i plug the Mask Texture into BumpOffset of the next layer. But the fact is that now mask takes Height from this Bump Offset of the next layer and mack slips down. How i can change this code to make it work?

Thank you in advance. Sorry if the problem is not very clear, english is not my first language