User blog comment:KarasuGamma/The Future Pricing Scheme/@comment-8221180-20130415094749

Well, as you mentioned a few times, it does seem like Riot only considers the age of the champions. If it comes like you theory-crafted, it would indeed take quite an amazing time for brand and the likes to be lowered.

But the only thing we know is the planned shedule. Before they told us about it, champions go pricing reduction as a surprise. So my theory is that, outside of this plan, champions might get random pricing reductions.

My guess is that they wish to let the 6300 tier stay steady at where it is right now, as you mentioned as well. But below that, everything is totally random. we go 4 additional tiers (450, 1350, 3150 and 4800) So they will reduce prices at a random time to surprise us.

Buuuut that is only my wild guess.