edit: okay, after looking at the game script most of the stuff below can be disregarded. The game doesn't intend to set the time slots to 21. Instead, it's a repeated error in the script, where it tries to set variable to 0 and then increase, but it instead issues instructions
$ timeu == 0
which is a comparison, not assignment, and does nothing to the value of the variable. These pairs
$ timeu == 0
$ timeu += 14
should be replaced with a simple
$ timeu = 14
instead.
Not sure if this is error or oversight, but in Week 4 there's a distinct difference between what the game tells the player and how it plays out in terms of mechanics.
At the start of the week you're told that with Matchmaker business out of the way and with everyone spooked by murder and not doing any social stuff, you'll have much more time at your hands than before. And the "Time" panel which in previous three weeks starts at 14 (2 activities per day) is set to 21, which implies you should be able to pick 3 activities per day.
Except... nothing actually changes compared to previous weeks -- you still only get the same 2 slots per day. Add to this that couple of slots are typically blocked by social visits (one from potential partner, and one on Friday with murder clues) So you're effectively left with 10 slots before the trial, and out of these 7 are needed for full investigation, and 1 for personal plot. Leaving you with mere two slots to do anything else. Which is hardly much more free time you're supposed to have. And incidentally means if you haven't had the skill levels needed to perform investigations at the start of the week, there's practically zero chance to address this matter.
If this sort of crunch was intentional, then the Time variable on the Info panel should be perhaps adjusted so it doesn't mislead the player that they have more time than they actually have. Though it'd be probably far more considerate to instead do what the game claims and allow an extra activity per day, for more leeway.
(on a side note, it's also a bit frustrating that when you choose to explore the staff quarters MC suddenly turns braindead and even if they know about certain "Lee" who died and whose identity is pretty much known at this point is likely connected to this murder, they are only capable of searching through his room if Kade deigns to tell them so. But that's technically not a bug so, ehh ._.)