large part of the economy still revolves around b grade items, and right now u are manipulating large part of that economy by adding b grade that soon into the game.
i think everyone understands that any server nowdays is about the money, and we still play.The issue here is that u add those items way too soon, and by doing that everyone is afraid that u will add a grade in 2 weeks and maybe noble or sub or s grade in a month, making ppl that want to play the game because its fun and not because they can make $$ out of it, quit.
How do u stimulate RMT ? Well thats easy, now that u've put price tag on b grades, even ppl that dont RMT can easily RMT because u just gave real money value to x item.They dont need to be engaged in shady websites/organizations to RMT, u make it easier for casual ppl to RMT as well, therefore only making the RMT problem bigger.
Even a person that plays for fun, now values his bop to be worth x amount of $$.
And even if u think you are not really adding to the RMT issue, then again u are still interfering hardcore with the economy.