I do the same, but mainly so I don't confuse myself.All of the primary supplier's boards are "Acid Free" but not necessarily conservation. They sell white core decorative mat boards. I don't sell any white core decorative board since it is a bit deceptive to those who use or buy them thinking they are the same as conservation. If I were to cross this line I would gladly sell the white core decorative boards at a $9.95 retail price.
I have held firm in that anything coming out of my store with a white core is a conservation board so if it has my name on it and the core is white there is no confusion or deception.