If you have a range of 0 = left, 64 = center and 127 = right you can nearly do it.
If you set the range 127 to 0 (note the order is a bit strange, but increment doesn't work the other way around) you would think that you just need to increment by 64, but then you get 0, 64, 0 , 64 etc. because 128 = 0
You can either increment by 63 and get 0, 63, 126, 0, 63, 126 (left, nearly center and nearly right) or have a range of 127 to 1 and increment by 63. This gives you 1 , 64, 127, 1, 64,127 etc. (nearly left , center and right)
.easypar CC 1 10 127 1 increment 63
All the best
Royce