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Humans are not too good at predicting what killer whales will do. Whales tend to follow the herring, who tend to flee the whales, leading to a rather complex dynamic.
For some years, Tysfjord (between Narvik and Fauske) was the place to be to watch killer whales. We saw dozens of them in November 2005. Since then, they've apparently moved on to Vesterålen, but I've also understood from the documentary Blue Planet II that some are back in the deeper fjords inland, possibly including Tysfjord, but Blue Planet II tends to to be too specific in describing where they shoot (probably for the better, to prevent tourists loving the place to death; but I think I recognised Tysfjord in the background of the making of documentary section; and although Lofoten in summer is close to being loved to death, Lofoten in October/November is not, and Vesterålen or Tysfjold in November certainly is not). But that was shot several years ago, and they might be somewhere else yet.
Perhaps the best strategy is to ask some fishermen. Everybody follows the herring: whales, birds, fishermen. The language barrier with fishermen is smaller than with birds, fishermen will know where the herring are, and probably the whales are there too, but that doesn't help you too much in practice if the tourist company offering tours is located 60 km away.
You may be a little early at the end of October, but it's worth a try. I'd recommend going through the different companies in and around Vesterålen and Tysfjord and see what they have on offer, and if there are any traveller reports from 2017. You can get to Tysfjord by ferry from Lødingen or from Svolvær and then drive from Skutvik.