I guess eHobby gave Megaplex blue bullets to further differentiate him from reissue Megatron. That and it better matches Megaplex's blue highlights (whereas the red bullets match Megatron's red highlights).

Well... this kinda makes my acquisition for today pretty pale, but I got Animated Skywarp (on sale at Uncie Pete's, thanks to liegeprime for his assist). I also got HA Mudflap & Chromia yesterday just cos I want Agent Simmons, so I'll be listing those Autobots for sale soon in the sales yard.