It is true that the AIM holding entry recommendations are only recommendations, but some important people in the industry treat the AIM as regulation. I know a couple of Des and an FAA examiner that would fail you if you did not enter the hold as the AIM recommends. There are some employers who also only want to see the AIM entries. The time you take now to perfect holding entries so you can comply with the AIM will make your life/career easier if you ever run into an AIM stickler.