Firing from Open Topped Vehicles

Somebody pointed out to me yesterday that if my Raiders/Venoms move 12" the squads inside have to disembark to be able to fire. I've been playing (and nobody has corrected me but I could be wrong) that if they move 12" the Vehicles & the squads inside can fire. Which way is right? Do I have to disembark or only move up to 6" for my squads to fire? I don't care which way it is I just want to play it right!

BRB p.66 wrote:

Models firing from a vehicle count as moving if the
vehicle moves, and may not fire at all if the vehicle
moved at Cruising speed that turn.

A vehicle, that moved more than 6" always counts as moved at cruising speed. (unless you're a red ork)
A fast vehicle may shoot more weapons, when moved at cruising speed, open-topped vehicles let all passangers fire, not just one per fire point, but the rule that they may not fire at all if the vehicle moved more than 6" is never revoked.
Note however that they may disembark, counting as moved, if the vehicle has not or will not move flat out (more than 12") and as most of our units may still fire, after moving, they may do so; because our transports are open-topped they may even assault.

Thanks for letting me know. I think its funny that if the vehicle moves 12" they can't shoot, but if they move 12" and then take the time to get out of the vehicle they can haha. I guess it's because otherwise it would make us too strong, so they had to make the mechanics fit the game play and not common sense.
(Oh no! I'm turning into one of those people who think the rules should be like real life! Haha just kidding..)

I think that's one of the wilder inconsistencies they'll have to address in the next iteration of the rules...

Another being this:

if the vehicle gets hit and damaged such that it can't fire, the passengers inside are similarly affected. Makes sense.

Those passengers can still disembark though, and which point they can fire as normal.

Makes sense if you don't think about it.

It's rules, they don't make sense, by default.

But I hope this gets fixed in 6th ed.