Well that explains all the transferring of wort and rising and falling of the mash tun level we observed.
I was reading Wild Brews[/url:1gtvho5e] and the author explains where these weird mashing regimes came from. At one time, breweries in Belgium were taxed according to the size of the mash tun, so if you could pack your tun with grain and then pump wort to other vessels, replacing it with more liquor in the tun, to make more wort, you could maximise the amount of beer you could make per brewday, with a minimum tax bill.