Custom field/column – price split

Hi

is there any way to add additional price info / column to this ecommerce platform?

Let me explain what i need. A customer come to my website with e-literature (simply ebooks but not only). He/She can buy it in a three different pricing options ( e.g. 5$, 10$, and 15$). But before checkout should appear a slider/input, which will pass to database (and be visible in plugin sales dashboard) what percentage of the product value/price will be dedicated to the store owner as store owner fee. so if somebody will decide to give me 50%, in the dashboard i will see column (owner 2.5$ and column author 2.5$). Payment stay as it is – everything goes to me as store owner, and i will send money to the author without involving ecommerce system. In other worlds – i need an extension for creating custom fields in the WPECOMMERCE and integrating them with it.

https://wordpress.org/plugins/wp-e-commerce/