Hmm, interesting that they've coined him Gigatron - I wonder if this is perhaps due to Hasbro wishing to use the Overlord name themselves?

I don't buy the explanation of "The U.S. only knows him as Gigatron" as it is a load of Beryllium Baloney , and I doubt it'd be due to Copyright either as they'd just slap "Decepticon" in front of "Overlord", re: Decepticon Overlord , so what other possible reasons might there be?