When using testforblock to check if item frames with maps are rotated correctly will sometimes return false.

https://www.youtube.com/watch?v=tlYFKcyD0EU&feature=youtu.be

I suspect that for maps. the rotation of the maps is multiplied by 2.
Itemframes can rotate its items between 8 positions. Maps only have 4 rotations.
If you rotate the map 1 revolution it is the same value as an item that has only rotated half a rotation.

It would be better for detection purposes if maps increase their values by 2 each click instead of multiply the rotation by 2