start when activate multipage on form ?
 

I'm using a form consist of 6 multipages.

On the last multipage, page 6, I'm having a lot of statistic about my
customers.
What I want is that when you activate page 6 then the calculating on
the statistic should begin.

I could do this calculating when I opens the form, but I'm afraid that
this calculating will take a few seconds and I dont want the users to
wait each time they opens the form.

So how do I start the calculating when the users, use multipage 6 ??