Just looked at our 744's FCOM2 and no mention of VMCA 2 at all, it only mentions VMCG and VMCA in the definitions section. "Failure of the most critical engine at takeoff thrust etc........"
The computer Takeoff data we get in the flight deck from the ACARS system only mentions VMCG.
In fact there are no tables to calculate VMCA or VMCG in our FCOM 2 manuals for the 777 or the 744.