I am not sure what the abreviations RLA and MCA mean. If you have the 2002 NEC, you may want to look at Article 440.22. If they used values you have for RLA or MCA to size the protection they may be sizing the wire to that also. If the feed is directly to your equipment, it definately sounds like whoever wrote the revision is confused about the supply requirments. Does your equipment have circuit protection or a disconnect means on board? Are they planning to install any other equipment ahead of your unit? ie a panel 277 lighting. If they have to set a disconnect they maybe oversizing and bringing a grounded conductor for future loads.
NEC Article 250.122 (F)(1) "Conductors in Parallel" requires a grounding conductor in each run sized to the rating of the over current device. With a 1200A disconnect 3/0 copper would be required in each raceway.
