There's always a curve for each SAT test so that they can match the previous ones. Sometimes if they make a harder one in December, they are gonna curve to be the same results as the easier test for example May. I wouldn't depend my score on it 100% though as it is not guaranteed how big of a curve you would receive.
Crazy that 3 wrong questions on reading is a 740. Score jumped almost 100 points after applying Dan's predictive strategy on the reading section. Thanks!