Sourdough in a bread machine

My current bread machine has user configurable programs. The rises only go to 2 hours and there is not the possibility to mix, rest then knead. Short kneads between the rises are also fixed at 15 seconds. I set the machine up to:

Pre-heat: 0
Knead 1: 3 mins
Knead 2: 22 mins
Rise 1: 1h
Rise 2: 2h
Rise 3: 2h
Bake: 55 mins
Keep Warm: 1h

I don't quite get why there are two kneads - there is only the briefest of pauses (a second or two) between them. Those rise times are the longest I could get.

I used http://sourdough.com/recipes/rye-loaf-750g but added more white flour (quite a bit) to get a dough that the machine was mixing like any yeast bread.

I'm pleased to say that the result was a reasonable loaf - low rise compared to a yeast based bread but not that different from what I usually get from my sourdough breads.

My machine is a Kenwood BM450, but I doubt it's the only one with programmable settings.