The "gradual refresh" method you read about was probably related to the power steering fluid where it is recirculated throughout the system and Newton's method of approximation will lead to a 90+% change after a few empty/refill cycles of the reservoir. Brake fluid doesn't circulate, except by diffusion, so must be bled to be fresh at the caliper cylinders. You got to be on your back for the brakes, one way or the other (unless you have a lift
).