Complex calculations. Pricing table lookup

I've a large ecommerce project is for a blinds manufacturer that requires some complex pricing so looking to use gravity forms and linked to woocommerce cart. A somewhat similar site and concept to what we need to do is
http://www.tuiss.co.uk/roman-blinds/3861/essential-natural.htm

Price calculations are quite convoluted. The pricing calculations are not a normal dimensional based around area though, but is more table based due to overlaps of materials etc. He has 6 pricing spreadsheets that will be assigned to the various product groups. Here's one
https://www.dropbox.com/s/a2uz1i77uecnpyh/PRICE.xls

If I have separate forms with length-width for each price group, but need the result to come from a fixed data above. Can dynamic population be used in some way to pick up the right values if these are 'stored' in another form as entries in specific locations? i.e. setup the tables off the pricing spreadsheet as a separate form and then have the result imported dynamically based upon the width and length input? Having the data held in another special for with all the rows and columns filled in. A form would be ideal since we could likely import a new one when pricing is changed. Or is there another more logical way to do this?

I've never done anything this complex or used the calculations, conditionals or dynamic features of GF so any guidance or tips would be welcomed to save me going in the wrong direction. I do understand it will likely take a while to set up...

Thanks David. Think we understand. Do you have any documentation or examples that could assist? I also see there are now tools to do entry import to GF itself, http://wordpress.org/extend/plugins/gravity-forms-mass-import/
but presumably what we want to do here is to have a new table in the sql db to store and access the pricing data? Again, this isn't my area of expertise, but eager to learn or alternatively outsource to someone who could do this bit.