Why does changing the Business Description change the refund amount?

Why does changing the Business Description change the refund amount?

 

If I type in the following, my refund for federal and state change significantly. Why? What is triggered by the Business Description?

 

Refund amounts are examples only.

 

agriculture / Federal $1711 / State $337

Agriculture / Federal $1271 / State $252

farming / Federal $1271 / State $252

Farming / Federal $1271 / State $252

 

Lower case letter is creating a bigger refund.