The score says how it ended. xG says how it should have ended: it is the sum of the chances each shot was worth, not an opinion about the game.
A draw, but Hull City created more (1.80 xG against 1.21) — points dropped.
Chelsea: +0.9 for the season (10 in the table). Hull City: +2.5 (8). The gap between points and xPTS is built from matches like this one.