I see what you’re saying, but I don’t think that pattern is in play here. These are four independent clauses, not pairs of dependent clauses. If we supply some pronouns, it may make it clearer. So, to paraphrase:
When he looks up, I seem ever higher. When he bends down, I seem ever deeper.
When he advances, I seem further away. When he retreats, I shorten the distance even more.
Fu is not “cover,” and cu is not “quick.” Cu here is more like “close, near to.”
The character for fu in the version you cited is incorrect. It should be fu3 with the person radical. See: http://zdic.net/zd/zi/ZdicE4ZdicBFZdicAF.htm
It means to bend down, contrasting with yang3, which means to look up. These often appear together. In fact, the four verbs in play here have been used as a cluster: “fu yang jin tui,” referring to manner or deportment.
I’ve certainly seen many cases of the yu A, yu B pattern you mention, but I haven’t come across examples of mi A, mi B. There may be examples, but the line from the Analects which the Lun is quoting does not read that way; it’s two independent clauses: “The more I look up at it, the higher it soars; the more I penetrate into it, the harder it becomes.”
What do you think?