To my knowledge, stages or zones on the afterburner allow more lee-way in terms of afterburner-control.
In the old days, the afterburners were basically ON
, and guzzled a thousand pounds of fuel every minute. Adding some ability to have more control of the afterburner, the J-79 was fitted with a modulated afterburner with five different settings. The highest setting had the most thrust and fuel burn. The J-75, at least some models, featured a Min-AB, in addition to a Max AB
The J-58 used on the blackbird, has vernier control over the afterburner; able to regulate it just like one would regulate the engine RPM.