Hornresp Filling settings not taking effect

Hi there good people, quick hornresp question.

I'm using hornresp to design a tapped tapered transmission line. I have found a configuration that looks very promising, but cant seem to get the filling to stick.

it works fine in the loudspeaker wizard, and the spl graph looks great however clicking save on the wizard, and then calculating, it shows the old spl values without the effects of filling.

Am I missing something?