ASUS/GIGABYTE's 8+2 phase is indeed a 4+1/4+1 phase design. It was an AM2 socket design contstraint and the board is only able to have a true 4+1 phase design. That didn't stop manufacturers from doubling up though.

As for my board's 6+2 design and BIOSTAR's 6+2 design I'm not exactly 100% sure on how they achieved that.