You summed it up, but likely your estimated 30 R districts will be multiplied many times over nationwide to delete R districts and create new D districts (after all stimulus funds were appropriated to districts that didn't even exist).
How can anyone mail it back before 4/1? The question asks how many will be living there on April 1st. So in order to be truthful don’t you have to wait until 4/1 to mail it back?