No, they're not cabled at all. They end up just like any good Flemish twist string, you just don't have to individually twist every twist. It's described really clearly in TBB2, but essentially every element is the same - same number of bundles, same feathering and tapering etc. You just tightly pre-twist the areas that need twisting by rolling them on your thigh, put the two bundles together and twist again, the other way.
You actually end up with a much nicer, tighter string than doing each wrap by hand, because the thigh-rolling keeps the twists way more even and tight. It's a much faster way of getting a much better string. Win win!
What's really nice is that if you're doing a proper primitive string with something that has short fibres like linen, you can pre-twist the entire string using a simple drill jig, and end up with the whole string reverse-twisted just like the laid in loop area but massively stronger. I recently used that method to reverse twist a beautiful linen string for a 135lb elm bow, and the entire string took perhaps 10 minutes, and most of that time was spooling out the starting material.