Just like Misa said earlier, the company wanted 
to make this scene nice and fluid.  When making a 
movie, the animtation tends to be smoother since 
they do use more cels per minute then your 
average anime on tv.  I heard that for a minute 
of screen time, animators can draw over 100 cels 
for it.  That number could be wrong, so please 
don't quote me on that.  So yes, I also believe 
that your cel is a true production cel.

Hope that helps!

Hime