Game of Japan and Hit-Japan are definitely two separate entities. I do believe that Game of Japan still source some (if not all) of their stock from Hit-Japan though.
I've also noticed prices doubling on some titles at Game of Japan and in a very short time frame. Another strange thing I've observed is that I've purchased a game at let's say $20 and received it fine etc, but when I go back to the same product listing the price has doubled to $40. It's like every time they sell a copy of a game they just keep bumping up the price.
Hit-Japan has also bumped its prices up a bit, I've seen things like boxed Famicom and Mega Drive consoles which used to go for a steady $60 BIN (less with an offer) jump up to $90-$100.
In any event, my ordering experience between Game of Japan and Hit-Japan is always very different. Never had a problem with Hit-Japan in any regard, but have had to deal with a bit of crap from Game of Japan. E.g. Taking 2 weeks to despatch my order, waiting 2 weeks to inform me that the items I've ordered aren't in stock despite them being listed as in stock on their website and lastly some very rude responses to straight forward questions that I've asked.