Sorry for the ambiguous title, i'm not sure how to word it properly.

What i mean is this:

If a player finishes a Feast season in the Platinum tier, they should be awarded the Platinum achievement, along with the gold, silver and bronze achievements as well. There's no reason that we should have to hold back our ranking to collect achievement points and risk losing top 100 rewards, if we are capable of achieving diamond, but don't have the platinum title yet.