It is very interesting for B2s to hold also a B1. I am B1B2 on 2 A/C types but
AB2 only on another one. We had an audit from our quality department the other day we've been all amazed how narrow the scope for release is for B2s(ATA 22 23 24 31 34 45 only).
In my company most of the trouble shootings are performed by B2s. Most of the B1s have no idea about capacitive fuel indication systems for exemple...we most of the time perfom T/S on APUs, fire detection systems etc...
The jobs a B1 can't release are quite rare.
regards,
og