How very embarrassing for myself to have missed that line in editing! It shouldn't be there as that was a relic from the old dice rolling system. Dice Values (DV) are d4 through d12. You will not be rolling only d6 in this game!
You modify both DV and total through a lot of different effects. So, if I have a Fight DV of d6, with a +1 F DV modifier, and +2 F bonus, I would roll a d8 and add 2 to the total rolled when using Fight.