OK -
I'm playing in a testing hood and Beau (he's the younger one, right?) transitioned from toddler to child at 1pm.
Never do this post-NL. With NL cars, the grade-loss ding is applied at 1400 for children, 1200 for teens. If you transition at 1300, your sim will be a child at 1400, not in school, and therefore will be immediately penalized for not going, even though it wasn't possible. Pre-NL, the penalty was applied at 1000, an hour after the school bus left. Same story applies to missing work, but when you get a new job, you get a special "Does not have to work today" bit set. However, no such analogue exists for school, as there are no exceptions for school attendance, sims must always attend or be penalized. Don't transition at odd times, only use the 1800 transition.