Back on 12-07-04, a thread was started in the NEC forum, "What do you guys think?'" , where the drilling of holes in engineered wood I-joists was discussed.
As luck would have it, at that time I was dealing for the first time with I-Joists. The attached pic shows the results.
On the left side, you can just make out my first run of MC, as it winds back and forth through the totall non-aligned factory knock-outs.
On the right, you can see some much neater runs, which took advantage of holes drilled according to the manufacturers' spec sheet- made available to me through this forum.