Not all blocks are strikes. I teach what I call a "plow block" (using the flinch reaction to get arms between the attacker's shoulders and your upper targets), and have seen instructors teach a block that uses the arm at the side of the head to shield against a blow from the side. Neither are strikes.There is no such thing as a block...is not a block a strike that is striking what is striking, so a block is really a strike, which makes a simultaneous block/strike a normal action.