Flexible Y-Axis in a Waterfall chart

Hi,

I have created a waterfall chart based on the following website

http://peltiertech.com/Excel/Charts/Waterfall.html

The chart shows the changes from Budgeted Revenue to Actual Revenue.

Problem :

The chart is based on revenue numbers on a regional level with a drop
down to select any country within the region also. For eg. The Budgeted
Revenue is $50m with a variance of +/-2m to arrive at Actual Revenue.
Inorder to amplify the impact of the changes, I have set the Y-axis
scale to start at $47m. The changes (Plus and Minuses) become too small
to have any impact if the scale is set to start from Zero.

However when the user selects any country (the revenue can be from $30m
to $5m in various countries), the graphs disappear since the scale is
set at $47m.

Is it possible to have a flexible Y-axis scale which considers the
Budgeted Revenue(which can be from $5m to $50m) and sets the scale
which is $2m lower than the Budgeted Revenue so that the changes make a
proper visual impact.

Regards
Sandip.