Bulb help

I'm trying to replace my bulbs. Now either I'm retarded or the damn manual is wrong. I bought 2057 for my brake lights and reverse lights, because thats what the manual says and the Pep boys computer says. I get home and they only fit the brake lights. So instead of them going to waste I try to replace the rear turn signal bulbs. Wrong again! The bulbs I need have 1 terminal at the bottom of the bulb and the 2057s have 2. If this is the case, why is the manual wrong? Thanks.

Your brake light are 1157's your backup lights and turn signals are 1156's

Thanks.