Yes, though the two things you mention are separate and independent.
1. Your cellular provider is just another another Service provider accessed through BT instead of SPx. The speaker and mic of the 1062 take the place of those on the cellphone. And you can initiate and set the call destination from the 1062 instead of the cellphone's keypad or address book.
2. Primary Line can be set to any of SPx, BT, Obitalk or OBiLINE if connected.
