Advanced combat is a somewhat disingenuous name, as it implies that these rules are more complex than the "basic" rules found in the PHB. In truth, some of them are and some are not. Mostly, we look at these rules as a revision of the existing rules to make them more useful to players and DMs. In part that means taking incomprehensible portions of the combat system (grapple, for example), and cutting them down into discreet actions people can actually use without a half-hour argument. Partly this means taking basic combat actions and making sure that they have a valid purpose at all levels of play.