Dell MD3200i Controller 1GB Ports

I was told by support today that they don't recommend having all four ports from each controller on the same subnet.  I was also told that if that is the setup, only nics one and two on each controller would actually be servicing the array.  I'm a bit confused to say the least.

using vsphere 5.1, have multipathing configured correctly on the vsphere host side, connectivity back to the array seems ok, just curious to hear thoughts on how those ports should be configured.