I feel like these formulas are asking "What two move types will get me the maximum number of 4x effective hits" rather than "what two move types will get me the best neutral coverage". If you favor getting 4x effective hits rather than the concept of "trying to get the best two moves that will avoid you getting walled" then ice does get overrepresented, so there is a difference.
I mean personally I'd rather have better overall neutral coverage than the two moves that deal the most 4x damage, as this means you get less coverage overall(like comparing Fighting+Ghost vs Fighting+Ice), but I admit that you could also go the route of answering the question of "What common 4x weakness do pokemon who typically switch into this move type have?", hence Fighting+Ice.
I would say that in situations where you have more than two moves available, aiming to get more super effective coverage will be more useful, as you have the additional move to provide greater coverage, but if you only have two moves, I think aiming for neutral coverage would be better if you're trying to sweep and don't want to get walled. Like in in the case of M-Heracross you could go Close Combat/Arm Thrust+Pin Missile+Rock Blast or if you only had two moves available for attacks, Close Combat/Arm Thrust+Knock Off/Shadow Claw.
Of course these arguments are being presented with the goal in mind of wanting to stay in as much as possible for a sweep. If you just wanted to use something to act as a lure and weren't so concerned about switching out, then you could probably get away with stuff like Fighting+Ice as long as the rest of your teambuilding was good, though my opinion is that the more hard switches you do, the more momentum you're going to lose. VoltTurn and Baton Pass strategies are effective for the same reason: they provide a method of being penalized less for predictions, potentially attacking something without taking any damage, and making it easier to react to what the opponent has, because every single turn it's giving you an opportunity to switch in something else to better handle the current threat. Both of them do this, but Baton Pass was worse because of the ability to accumilate boosts.
So if the goal is to try to stay in and sweep, which generally I think translates to attempting to get the best neutral coverage, then we should be seeing a lot more of *insert move here*+Ghost(though you could make a case for Fairy or Dark depending on whether it gets STAB). Having ice everywhere just makes it feel to me like you're trying to lure in specific dedicated walls, and that's fine, but I think that's something different from just having the best coverage.