No Prep Time
Setting Sacred World of the Kais
@othus12: I think it has something to do with power from the transformation leaked into his base form. Like how it looked like he got stronger after achieving super saiyan. The transformation could have came with a increase to the base power of the user. Also Bills could have been weakened from fighting ssjg Goku as well.
@othus12: I don't really know but it looked like he was putting out more strength then super saiyan three. Though that could also have been because of the ritual required to unlock ssjg using the power of 6 saiyans I am guessing they gave Goku some of their power though what power would Pan have? I really want to see that movie just got to wait for a sub version to come out online I guess though.