Usually in an A/B the bark is heated up in acidic water, then the resulting "tea" is filtered and the remaining solids are put back in more acidic water and the cycle repeated again with the tea being collected at each stage because that's where the dissolved DMT salts from the bark end up.
Then the bulk tea can be simmered down to a more manageable volume before base is added and NPS used to pull off the freebase formed by adding base.
If there's no filter step then you may be looking at AtB or Acid to Base where the distinction is that acid is used to help break down the plant matter, but base is added without filtering. ... it's really just a subtlety around naming
Is it Cyb's tek you're looking at? That's an AtB and won't scale well to over 150g or so due to the bulk of liquid required. It is however a great Tek for smaller extractions and, personally, my go to tek as I've always found so far that yields are better with many small extractions rather than one large one.