In Poser 6 when I try "Jessi" and "JessiHiRes", the figures scale up and down as they should, even along the individual axis.

JessiCasual is another matter!   She doesn't seem to scale at all. Just gets pigeon toed and moved upwards above the floor a bit when the scale dial is turned to the right.  When the scale dial is turned to the left, she sits.

Here are images.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi