ok, here is the answer.
frequently, when a person is starting a cutting, they will "over love" it in an effort to "hurry it along".
when a cutting is started in a pot with an established
plant, the care of the established
plant is usually followed, making it easy to properly care for the cutting.
an example is with peace lilies. if you put any kind of cutting (non
succulent) in with a peace
lily, you can be sure that it will get enough water, and won't be over fertilized because peace lilies are sensitive to both things. so they tell you when they are thirsty.