Armor: Greasy Kra'Vak Stuff?

Hello All:
	There is a debate that is raging in my FT playgroup.  The house
rules
state that there will be no mixed technology ships in normal FT play. 
However there is one major exception: Armor.  Human ships can purchase
Armor at normal cost.  How can this be when the rules of the house
prevent hybrid tech ships?  The guy who runs the group states that it's
because of the wording of the rules in More Thrust.  I refer you to page
25 and the rules under the caption of "Kra'Vak Armoured Hull Costs:"

	"When costing Kra'Vak ships (or indeed any other vessel fitted
with an
armoured hull)..."

	It's from that phrase where our fearless leader has devised the
ruling.  Needless to say, some players (namely Kra'Vak players) don't
like the ruling because they claim that the rules are for backgrounds
other than the offical background.  They think that the non-Kra'Vak
players are just trying to sqeeze a few more weapons systems into their
ships rather than paying the extra 3-9 MASS for protection.
	Personally, I like the ruling.	Who ever said we were playing in
the
offical universe to begin with?  Any thoughts?

Later,
Mark S.