Fanon Discontinuity: Ned being 60 has since been ignored and his previous background as the son of beatniks being retained.
Genius Bonus: Reverend Lovejoy tells the congregation, "And once again, tithing is ten percent off the top. That's gross income, not net. Please, people, don't force us to audit." This is both a religion and economics joke. In Christianity, it is customary to give ten percent of your weekly pay to the church (see Genesis 14:20, among other verses). The congregation was presumably giving 10 percent of their regular paycheck which would already have taxes deducted (the aforementioned net income) along with whatever other deductions they could claim, hence the auditing remark.