IBM´s TPC-H claim revisted - or: Has IBM something to hide?

I thought a little bit about the TPC-H benchmark published by IBM yesterday. There is something in it, that leaves some question. The p570 is a 8 socket system. You can build it by stacking 4 two-socket boxes with some special cabling. That´s one of the points behind buying a p570. Nevertheless, the configuration of the benchmark didn´t worked that way. They had 32 of this p570 building bloacks and used this boxes as 32 distinct systems making the p570 buildingblocks to an expensive volume server. By using the capability to build bigger systems ot of those building blocks you would have 8 instead of 32 systems to manage. The questions: What´s the reason of using such a configuration? Is there a scalability problem within the p570 giving you less return for the socket in bigger configurations ? What´s the impact to loads with higher dependencies between the partitions? I would like to see the performance numbers for a system with 32 p570 buildingblocks in 8 systems with an otherwise equal configuration.