Different strength training authors from Ellington Darden and Mike Mentzer to Dorian Yates and Gordon LaVelle have called their system HIT, with each individual having credited Arthur Jones for the formulation of its basic tenet principles. However, there has never been a clear and consistent guideline on how to utilize HIT. Darden advocated full body routines, while Yates recommended to split the workouts into four different sessions a week. Mentzer believed that no more than one set to muscular failure per body part was all that was required,  yet Yates and LaVelle believed that more than one exercise per body part is necessary to get complete development as a bodybuilder.
The second table, using a variation of alternating periodization, is more "hip" because it's relatively new to American strength training. Despite this, West German sports scientist Dietmar Schmidtbliecher, one of its early proponents, was writing about this method some 20 years ago! So, in reality, it's no more "new" than linear periodization. I find this method to be effective for those who have the necessary experience to handle more radical shifts in their program, and for those who are more interested in size than strength. It's certainly effective in keeping the body continually adapting!
Week 1: 75% of 1RM – Goal of ~30 reps. In general I like to use 5 sets of 6 reps. If you are used to doing just 5×5, that added rep on each set will be quite noticeable. It makes the workout quite a bit harder, but most can handle it at this intensity which is fairly low. You’ll find this easier on Bench/Press and harder on Squats but it’s manageable and it creates a pretty high “stepping off point” for week 2, so you can actually notice (and appreciate!) the drop in volume. If it’s too much then 5×5 is fine.