Cr Weatherall pipped Ms Butler by 57 votes in election results announced on Saturday, with 317 special votes to be added to the count.
The votes were expected to be added by Thursday, once verification by officials in Christchurch was complete, Dunedin electoral officer Pam Jordan said yesterday.
University of Otago political studies lecturer Associate Prof Janine Hayward doubted the extra votes would be enough to swing the result in Ms Butler's favour.
That was more likely if a higher number of votes were still to be included, or if the race was between only two candidates, she believed.
"Here, as I understand it, you basically re-run the iterations.
"I just can't imagine 317 special votes would do anything but continue the trend we see here."
Cr Weatherall on Sunday said he was awaiting confirmation of the final count before claiming the win, but had been told his seat should be safe.
Ms Butler said she was waiting for the final result before deciding whether to seek a recount.
Prof Hayward said council newcomer Jinty MacTavish appeared to be "the real interesting story" in results produced under Dunedin's STV voting system.
Results released on Saturday showed Miss MacTavish had polled 10th in the first round then dropped outside the top 11 as the rounds continued.
However, as more candidates were eliminated and secondary preferences reshuffled, she climbed through the ranks to finish fourth in Dunedin's central ward.
Ms Butler polled eighth in the first round, before dropping to ninth, then 11th, and eventually 12th.
The shifts indicated Ms Butler relied on a smaller bloc of supporters ranking her highly, whereas Miss MacTavish appeared to have broader support, but from people ranking her lower on their list of preferences, Prof Hayward believed.
"It's just extraordinary to see how much Jinty MacTavish rose.
"She's sitting there as the fourth elected candidate. She clearly has very broad support.
"That's the really nice bit about STV.
"It doesn't show blocs of support, it shows overall support."
