Need Help with Pricing by Attributes

Hello, this is the first time I am posting here and I have been searching the boards for a few days now and haven't quite found a thread relating the problem I am having.

I need to apply a discount based on the number of attributes which are text fields that are filled out. My form contains a list of registrant names. If 1 to 20 of the fields are completed, then no discount should be applied. If more than 20 are completed, then a 10 percent discount should be applied.

See http://www.niyc.org/zencart/index.php?main_page=product_info&products_id=1

You'll notice right now they all are listed as 105 by each registrant name field. This is where I need to apply a discount based on the number of fields completed.

Is this possible?

The version is 1.3

Thanks!

I am also looking to do this but dont know how.

I have a set of downloadable banners which I am selling. I have set up my attributes so that users can check the box next to the banner styles they wish to purchase, and each additional banner they select adds to the total item price. However, I want to make it so that if they only purchase one of the banners they pay £3. If they purchase 2 £5, for 3 £6 - so effectively each additional banner becomes cheaper.

Is this possible? There are lots of price fields in the attributes manager but ive no idea what they do. I am also using 1.3.

Thanks in advance.