I didn't, necessarily. I was only pointing out how the process generally works in my game. You were talking about telling a player no if they want to do something that's too powerful for what their character can do. I try to avoid that by having the players describe what they intend to do, and then giving some options with various mechanical difficulties and benefits for how to accomplish it.
Mainly, my example above, relates to the following section of p. 42:
Other Checks: If the action is related to a skill (Acrobatics and Athletics cover a lot of the stunts characters try in combat), use that check. If it is not an obvious skill or attack roll, use an ability check. Consult the Difficulty Class and Damage by Level table below, and set the DC according to whether you think the task should be easy, hard, or somewhere in between. A quick rule of thumb is to start with a DC of 10 (easy), 15 (moderate), or 20 (hard) and add one-half the character’s level.
And then, if necessary, referencing the chart for appropriate DCs.
But you're right... The actual effects of the different option are simply based on my own judgment, and what I generally remember from the actions and powers in the rulebook. That has nothing to with page 42, aside from the single example they give on that page (Level 8 Rogue: Acrobatics DC 20 = swing on chandelier, Strength attack vs. Fortitude = push one square into brazier).
At another time, in another situation, I might end up ruling it slightly differently because it's an ad hoc ruling, the situation occurs rarely, and it's simply not worth the time and trouble to write it down and dig it back up later. I've made that clear to my players, and they're fine with it.