I don't think that is correct. Right now they delegate ~15SP with the account creation with delegation transaction. They don't delegate more and then reduce it (just checked this with some new steemit-created accounts).
If the account creation fee is increased to 0.2 then I believe they would delegate ~30SP with the account creation with delegation transaction instead. I don't know if they will then reduce the amount delegated automatically afterwards.
When a new account is created, the @steem account delegates 30,690.000000 VESTS to the account as part of the account creation. Later, redeemer updates the delegation to 30,282.282907 VESTS.
If the account creation fee is doubled, the account creation vests would double, but there would be no reason to update the redeemer limit, since this is in place to ensure the account has sufficient SP for bandwidth purposes and is unrelated to the creation fee.