Drukhari Ship costs

Is anyone else really confused about the Drukhari battleship costs ? The cheapest one is SO cheap compared to some other. The one that replaces the Torpedos with a single launch bay costs 122 points more.

The one that doesnt have any torpedoes and no replacement just less weapons also costs more for some reason ? And then you have the one that has straight up 3 more lances than that one and thats only 12 points or so ?

It just doesnt seem to make sense.

Can anyone explain that to me please ?

the one without torpedos has a special assault boat. I don't think they are priced well nevertheless.