I'm pretty sure you have to upgrade each ship to get the advantage.... quite costly in the end.
Sorry, I'm really the only serious Ork player around, and I'm not too much a fan of that document. So there hasn't been much input for it other than 'Orks shouldn't have this' or 'Everything costs too much' etc.
I honestly greatly prefer the 'Waagh!' type list. The Clanz document is an attempt to make retroactive fixes on the Ork problems, rather than fixing the initial cause of them.
Escorts shouldn't be forced to be taken, in the case of Orks they should be good enough so that one would prefer them over Kroozers.
Also there is the retroactive fix of making warlords free, which is supposed to affect the overall cost of ships by making them relatively cheaper. Then upgrades to take things like lances... ugh...
Problem is that the HA can't (or won't) change a lot of things in the rules that are rather necessary to balance fleets, make the rules more noob-friendly and less like pulling a stick through mud to figure out. Not that they are bad guys, it's just what happens when GW is very touchy with what they are doing.
Sorry about the pseudo-rant. I'm head of the fan-group that is writing a revised version of Gothic.