Doubt it very much.. main cost of producing a transformer is actually making it with the core and  different windings.. a few less windings on the lighting side ain't going to make any difference... its only a few Watts or power we are talking about.. 6V @ 10Amps is only 60W... if every incandescent bulb was lit at the same time, you'd still only be talking around 40W max... in the scheme of things we are niggling over sheckles

Yes, I see your point. Keeping things the same could also be good for the mod'ers I guess, more head room on the lighting circuitry.