Is it ok to use Allison C4 spec. fluid in our trannies? Or just DexronIII spec.?

"C4 fluids are not approved for use in 1000/2000/2400 Series™ transmissions unless they are also licensed as DEXRON-III®. An approved oil list (GN3465EN) is available from your local Allison dealer/distributor or via the Allison website at www.allisontransmission.com (http://www.allisontransmission.com)"

Allison Fluid Recommendations (http://www.allisontransmission.com/documents/product/13-TR-90,%20Rev%20E.pdf)