From what I noticed, the higher the skill level (5-and up) your peep goes the slower it seems to make progress to the next level even using the "magazine". However, peeps on level 1 will jump almost to the end of that level if they read the "magazine" with the basic upgrade. When I upgraded my rooms and used the magazines, my peeps skill level jumps always jump to the next level (1-4). It does slow down at level 5 so I collect the "magazines" and keep them until I start a new generation in order to get the most from them.