The scale provided by Couture was an escalator bonus system. Couture was entitled to $1 per buy on buys 100,000 through 175,000, $1.50 on buys 175,000 through 300,000, $2 on buys 300,000 through 330,000, and $3 per buy on buys over 330,000. With most UFC shows now believed to do over 330,000 buys, under the scale fighters would be entitled to $322,500 plus $3 per buy for every buy over 330,000. While not confirmed, it is believed that the scale is not unique to Couture and instead represents the standard arrangement with other top fighters in the company.
http://mmapayout.com/2007/10/inside-the-ufc-bonus-system/