Sales Order - Discountable option

Hi, we are using 2014 Standard version 5.1

Have a question in regards to Hand Keyed Sales Orders and the Discountable option at the detail line.

for a certain customer we have a 2% discount setup.  when i go into Customer Maintenance we setup the Discount Rate at 2%.

Now i know if we click on the Discountable Option at the line level it applies the discount on the Totals Tab.

My Question is, is there a way to set this option only for this Customer so that the person Hand Keying this Order doesnt have to remember to click that box to make it Discountable??

i didnt see an option on the Customer Maintenance screens.

any help would be appreciated.

Peter