Oh yes!!! That's Chynna! She is what I call a shoveller when it comes to using the litter box. She likes to dig and dig right down to the bottom of the box and when she is finished she wants to make a mountain out of all the litter to cover it up.
I went and bought a litter box similar to the one in this link:http://img.alibaba.com/photo/1178965...Litter_Box.jpg
And that helped a great deal. The hinged sides lean inwards which prevents her from shovelling out the whole box onto the floor.
Abby on the other hand wouldn't be caught dead digging in litter. She goes and jumps out. Doesn't dig before and doesn't cover after.