As always when it loses a class action lawsuit in court, the Treasury chooses to provide a refund mechanism as a lesser evil. This way you can control the returns. Do not use this mechanism without an advisor. It is like trusting that the person who first took it from us, and refused to return it until he was forced to do so by the Courts of Justice, will return it to us correctly.
In all cases, the tax authorities are incorrectly calculating the interest to be refunded, always in your favor.
It is expected to do the same for requests submitted through this mechanism.