| toastedamphibian |
I think you may be confused.
If the BAB entry says +6/+1, your BAB is +6. The other numbers are just their to let you know you gain iterative attacks at the listed numbers.
A 8th level rogue has a bab of 6, not 7. If he multiclasses and takes a level in fighter, you would add the fighter BAB as well, so a rogue 8 fighter 1 has a bab of 7.