Taking longer means the file is active and the school is working the process. The school files. The NCAA reviews the file. They approve, deny or request more documentation. The school prepares and submits the additional documentation. The other school can contest claims. The filing school responds. The NCAA weighs both sides and approves, denies or requests more documentation. When the waiver is denied, the school either accepts it or finds out the reason(s) for denial and puts together new documentation to rebut objections.
Every time the school is asked for more documentation, it learns more about what the NCAA wants and can bring the case more in line with that. The squeaky wheel gets the grease. But it may have to squeak long and loud.