Hi there — welcome to the forums and great q’s —
Here are some thoughts — I hope you find them helpful and if you have any follow up q’s let me know —
1) As you alluded to, there is a significant difference between understanding a flaw and coming up with a way to describe that flaw. All of the reasoning flaws that appear on the LSAT can be phrased in a variety of ways, and, the more the challenging the problem, the more likely it is that they will describe flaws using different wording than you might expect.
So, (a) it is important to know that there is a difference between understanding the flaw and understanding a way to describe it, (b) you want to work on being flexible in terms of describing flaws, and, as (c) an added benefit, being able to think about flaws from a variety of angles often allows you to see or understand flaws better than you might otherwise. All of this will be described in much greater depth as you get deeper into the book.
2) Yes you are right in thinking that fails to consider and takes for granted can be thought of as two sides of the same coin. There isn’t a right or wrong between the two.
3) In terms of the Problem #12 from page 90 — perhaps I’m missing something that you are seeing, but I don’t see that it is missing any critical wording. A word like “most” would certainly make the flaw a more obvious one, but harder problems have more subtle issues, and to me, this is an example of such a situation — without adding in additional assumptions, or wording such as “from each individual employee’s salary,” the premise, as given, doesn’t guarantee the conclusion.
“Yatoo corporation has slashed the amount it pays in salaries by 6 percent this year.” “Amount it pays in salaries” describes an overall amount, and we can’t make the assumption that this applies equally to each employee.
“Jan has slashed the amount she spends on groceries” — doesn’t mean we can assume she has cut the amount spends on each piece of grocery by an equal amount.
“Tom has slashed the amount of time he spends with his friends” — doesn’t mean we can assume he slashed the amount of time he spends with each friend equally.
I understand that wording issues can be subtle and open to interpretation, and again, perhaps I’m missing something, but those are my thoughts.
HTH and if you have any follow-up let me know –