What size of parallel wire for 900 amp service?

Conductors by code are only allowed to be loaded up to 80 percent. In this case an over size wire set will be higher that what the wire is rated for in the code book. A 600 MCM copper conductor with an insulation factor of 90 degrees C is rated at 455 amps. Paralleled together will give an ampacity of 910 amps. After the derate the maximum amperage allowed is 728 amps. So to get the full 900 amp the wire size has to be increased to a 1000 MCM copper conductor with an insulation factor of 90 degrees C which is rated at 585 amps. Paralleled this give you an ampacity of 1170 amps. After the derate the maximum amperage allowed is 1170 x 80% = 936 amps