It seems I have been using type differently to many others, I envision your "type" or set functional order as a single layer, this layer is a person's most natural way of being, something they fall back on and feel comfortable with but beyond that, functional strength can be conciously developed in any way, right across the functions. So there will be a second layer which is functional ability and strength, this layer is influenced by training and practice.
Being a Se dominant for example, will give you a headstart when it comes to Se strength but their is nothing preventing another type conciously developing skill and surpassing the Se dom in the skillful use of Se.
To me frequency of use does not equal proficiency of use.
So with myself as an example I'm an SP, yet I know for a fact that if someone of a different temperament were to be trained by a professional in say the martial arts from a young age, their reflexes and awareness of the immediate environment would be better than mine but their type would still have remained the same, regardless of the massive increase in the strength of their Se related skills.
Does this seem right?