Problems with sizing the region 3

I’m having a problem setting the region3, I know that it has an specific order, but no matter the order I set, it always has a problem:

setting point1 at x, y, z
and point2 at x + 12, y + 12, z + 12

and viceversa

I’m using the the position where the small parts are, so both corners are properly placed, somehow the size is weird

Part.CFrame = Region.CFrame
Part.Size = Region.Size

That wasn’t the problem, both are the same.

I realized is because I’m getting negative Size parameters, so made em absolute and worked on checking the area, but now I got a diff problem.

It doesn’t detects if there are parts in the region, when the 100% of the region is filled with 99% of the part, why? Also why am I getting negative Sizes?