Yes, those bullets are probably on the soft side so they are recommending lower pressures.
You can safely build .44 Special pressure loads in your .44 Magnum brass using W231. There are other sources too if you want to push the pressures/velocities a little more but if the bullet fits well in your barrel you will probably see no leading.
More leading has been caused by bullets that were too hard than bullets that are too soft.
Missouri Bullets sells sample packs of their bullets. Their 44 Stalker bullet for $12.50 is 200gr .430" bullet with an 18 BHN you can push harder.
Missouri Bullet Company