If upset caused by a winner is 3 then which lowest seed can win the tournament?

Total number of matches in the 1st stage is 4 x 7 = 28, lets consider group 1 here if seed 1 won all the matches then remaining 21 matches or points can be equally distributed to 7 player (3 points each) and the lowest possible player would advance to next stage with tie breaker rule. In this stage seed 13 can get 3 points after 2 upsets caused by him. So from this group seed 1 and 13 would advance to the next stage. Similarly from 2^nd group seed 2 and 14 would advance to the next stage.
Now as per the rule seed 1 will play with seed 14 and seed 2 will play with seed 13,
If seed 13 and 4 meet in the tournament then seed 13 will win with 3 upset.