Having problems with translating negative edges (Ahead of time, I noticed that this seems to be a problem with negative translations. I will change the intro to show this.)

I am trying to create a wedge with angles on the lower end of the wedge, as shown in the pictures below. However, the left side translates correctly since it is a positive translation, while the right side creates a weird triangular edge due to the negative translation. Is there any way to have the right side of the wedge follow the same mechanics as the left side?

Lets say I want to change two of the vertices, specifically the top 2 on the lower half of the wedge. One will move correctly and will only be connected two its closest points.

EXAMPLE:



https://gyazo.com/b1e7b3a749a7b5b328f03166bd263c1a

But then when I do the other side It is connected to all points on the side plane.

EXAMPLE:



https://gyazo.com/3fb503ce3e24ad29baed76ad5112cf3a

Here is an example of both of them next to each other.

EXAMPLE:



https://gyazo.com/ce860346a5ac251920eafe7081f839d7

Is it possible to move the vertice on the right in the same way as the vertice on the left? I would like to make a nice angled wedge but its not possible with this happening! Would love some help!

Here is a Gif showing what I am having troubles with, in slightly more detail. Notice that the right side of the wedge creates an odd triangular edge while the left side is nice and flat.

EXAMPLE: https://gyazo.com/3f9ecc8a55b817a23314074f6a28512f
The origin remains unchanged when the object is modified in Edit mode. To move the origin, switch to Object mode and use the button Tool Shelf>Set Origin (or Ctrl-Shift-Alt C)
Possibly, check the Snap during transform options (the magnet icon or Shift-Tab)


To reshape your wedge, start from a cube, switch to Edit mode, disable the snapping, select the vertices to be moved, enable the 3D manipulator in Translate mode and drag the arrow in the 3D view.