Since they are the alternative to Firm Feel, they offer similar services.
No, the steering ratio is not changed. On the power steering units, that isn't possible.
What they do when the firmness levels are increased is use stiffer springs during assembly. The steering effort is higher to closer match the feel of a newer car.
The issue is, no matter what any rebuilder does, is that they are dealing with a steering unit that was designed in the late 50s and really wasn't changed much throughout the 30+ years that it was used in cars and vans. ALL of these have some amount of free play in the middle of the travel. You're driving straight and can always count on being able to turn the wheel off center a bit both left and right before the tires actually turn. This slop is due to the original design that cannot be changed. For at least half of those years, low effort power steering was often thought of as desirable and comfortable. People that once owned manual steering cars really appreciated how much easier it was to drive once power steering became common.
Once we started paying more attention to handling by switching to lower profile radial tires, firmer springs and shocks, the steering feel in most cars started to evolve from the over-boosted Mopar and GM products to a higher effort, more precise units including rack and pinion as well as refined worm gear and sector designs. Many rebuilders just take the units apart, clean them and reassemble with new seals and gaskets. Any slop it had before, it will have again. Quality rebuilders will replace worn parts so they at least feel better but will still have that free play in the middle.
Low mile originals and quality rebuilds will have LESS of it but it will increase over time and driven miles.
