Had a customer in today with the same issue as yourself. His body proportions were such that the larger bike with a plain seat pin was best for him.

I reckon that about a third of the bikes with a suspension seat pin go out with them swapped for a plain pin, something I am not afraid to do since I am not convinced that the obvious benefits of the suspension seat pin always outweigh the not so obvious disadvantages. These are that the extra height might compromise the ride position, the movement can be disconcerting and they sometimes squeak which is just plain annoying.