setting: R289, 14k yellow gold, in size6

center stone: 3.5ct F VVS2 10.67*7.38*4.92mm--$946, after 20% off, the price is $756.8. https://api.igi.org/viewpdf.php?r=662481996

original order store credit is $637.245 (749.7-15%)，the replacement ring after 20% off is $1177.392, so price difference is $540.147 (1177.392-637.245)