Your scoring average is based upon your best 10 of your last 14 scores. At this time a 9-hole rounds counts double towards your average. After shooting your 77 you shot a 43, which for your scoring average is treated as an 86. That is what drove your average up a few points. Also keep in mind that every score you shoot knocks your oldest score out of the equation, so there will be times when shooting a score lower than your average raises your average and vice versa. It all depends on what old score is kicked out and which one replaces it.