I have seen 5 mentioned, but you only need to do them until you can read below 70% SOH with the Soul EV Spy app. My guess is, with the battery so poor, three should do it.
I think the dealers actions are a cynical delaying tactic, despite the fact that KIA has instructed the dealers to read the SOH before doing the update. See link
. You might like to show that TSB to the dealer when you next take it in, just to let them know that you know.