Chart or graph with weighted values?

I’m interested in putting a feature for reviews on my site that includes reviews done with certain criteria, a few different criteria would make up the final overall total, but I’d like those values to have their own weights, rather than just an overall average.

For example:
Criteria 1 would be worth 30% of the overall total
Criteria 2 worth 30%
Criteria 3 worth 25%
Criteria 4 worth 15%

and then the average calculated based on that. Much like how a semester in school is weighted…final exam worth such and such %, participation worth x% etc.

This picture is of a plugin that shows the visual side of what I’d like to achieve, but it doesn’t have support for weighted values.
http://oi44.tinypic.com/2hi2pv4.jpg

Are there any plugins that would create charts with weighted values and allow for such customization as that picture shows? I’ve checked out what I can searching and can’t find much on the weighted values. Is there a different route I should take to achieve what I’m looking for other than a WP plugin?

Thanks.