Texture by face not consistent

[SacSurfin']

For texturing my roof tile I've found that setting the map type to plane and selecting the top face to texture is the most accurate depiction I can get but for some reason while using the rectangle in the mapping window to texture sometimes it goes one way and sometimes it mirrors. I have attached it to to the botom face since that would technically be mirrored from the top face, and it works sometimes and other times it looks right until I go to rotate then it mirrors itself and I can't get them to all have the same oriented texture. It seems like there's no way to get it right since you can never yourself mirror or flip the mapping rectangle and there doesn't seem to be a pattern, like the tile's angle or rotation. It just happens at random.