Custom Render Texture, globalTexcoord not on range 0 to 1?

I'm trying to use Custom Render Textures to generate a hight map, but for some reason the border of the chunks where never matched each other. So I decided to debug the uv value that come from globalTexcoord creating 2 chunks one with the value 0 to 1 and the other with a offset making its uv from 1 to 2.

The expected result was that they create a straight line, but looks like the uv value never actually reachs the value 1 (making some tests, looks like it stops near the value 0.996). There is any reason for this? And how can I make the number 1 to be inclusive?