Aaronic Priesthood duties

Not that this was a major cause for concern, but I recall being a little confused when, as an Aaronic Priesthood-holder, my quorums would have lessons about our duties in which we would research them in the Doctrine & Covenants. Section 20 spells things out quite clearly from the office of apostle (not an Aaronic Priesthood office) on down to deacon.

Apostles - ARE ELDERS, they are called to baptize, ordain others to Priesthood office, administer the sacrament, perform membership confirmations, teach, watch over the church, and lead all meetings.
Reality - apostles are high priests who wear dark suits and sit in on board meetings; twice a year they give a boring talk.

Priests - preach, teach, baptize, administer the sacrament, visit each house to tell them to pray out loud and to fulfill their family duties, ordain other priests and lesser offices, assist the elders, and take charge of the meetings when the elders aren't around.
Reality - priests stumble through a couple of written sacrament prayers once a week, baptize their younger siblings sometimes, and occasionally stand in with the Melchizedek Priesthood-holders when they ordain someone to an Aaronic Priesthood office.

Teachers - keep watch over the church, strengthen the members, make sure the members are behaving themselves, make sure the members gather for meetings often, and take over when there's not an elder or priest present, expounding, exhorting, etc., but not baptizing or administering the sacrament.
Reality - teachers go to church a little bit earlier than everyone else so they can fill the sacrament cups with water, put bread on the bread trays, usher, and clean up the sacrament table.

Deacons - help the teachers out, expound, exhort, etc., but no baptizing anyone or administering the sacrament.
Reality - pass the sacrament and maybe be the bishop's little messenger.

It was hard not to notice that there were a lot of things we were supposed to do but weren't being held accountable for. It was also evident that there were things we did that weren't listed as our responsibilities.

Who cares? It doesn't matter! That was all 1830 stuff anyway when the Church was small. We've grown, the duties of each office have been modified through need. Just be a good kid and don't do anything wrong, OK?

Sure, no problem. Oh, hey, where in the Doctrine & Covenants can I find the revelations that changed my Aaronic Priesthood duties?