What happens if two teams finish with the same %.

[RogersResults]

Adelaide and Port Adelaide both currently tied on percentage while both the Bulldogs and Hawthorn are tied on percentage. There's an outside chance we could see a tie in percentage this year for 8th spot.

Not quite ...
Adelaide: 102.9878048780487805%
Port Adelaide: 102.9751062537947784%

Although each has scored 49 pts. more than it has conceded, Adelaide has the lower pts against (7 fewer), which the way percentage is calculated gives the slighter better defensive team the advantage.

Also:
Bulldogs: 102.1712907117008444%
Hawthorn: 102.1519838601210491%

 

[HTPunter]

Yep, for them to actually finish equal they'll need to win by the same margin but with a difference of +-7 in the actual totals. Otherwise it's not actually equal.