Definition of Transit Duration

[TylerFair]

I noticed that the definition of the transit duration in nuance follows the "time for a planet to move from its sky-projected centre
overlapping with the stellar limb to exiting under the same condition" i.e. by doing epoch +- D/2 you obtain times corresponding to approximately the midpoint of ingress and egress (labelled T in diagram). I was wondering if there was a possibility to add a functionality for the transit duration under the traditional definition of first to fourth contact (labelled t_T). If this is too difficult or there are limitations thats fine! (Image attached)