In general, forward puts you ahead of the sidecut apex, making the ski engage quicker and more abruptly, backwards gives more float, but turn initiation becomes delayed and feels like driving a boat. Additionally, quite a bit of this is also dependent on (word vomit) how you like to ski as well as how you like to make the ski behave in a way that allows you to ski like how you like to ski. Some employee examples below.
Both Luke and I mount the Wildcat 108 at rec.
Luke (the form lord) prefers to drive the ski and mounting on the line rewards his aggressive, racer stance when skiing fast through a variety of terrain. Why doesn't he mount back a bit to give him more ski up front? Because this puts him behind the apex of the sidecut, making turn initiation slower and creating a feeling of driving a boat, where the turn is ever so slightly delayed from input to output, not something most ex racers are fans of.
I (the wiggle worm) like to ski with a more centered stance and tend to surf and slash my way through stuff, remaining light on my feet. I don't have the raw skiing strength or technique of Luke, so I try to 'bob and float' through chop and crud as opposed to simply bashing through it. Why don't I mount forward for added maneuverability? Because I like the consistency of the turn on the rec line and am not as much of a fan of the 'twitchiness' that can arise by bumping forward, as being in front of the sidecut apex will push the ski to engage quicker in the turn. I've adapted how I make the ski behave to allow me to remain on the rec line for turn consistency, while also increasing the maneuverability by being light on my feet (lots of keeping the tips planted while lifting the tails up / throwing them around, and being very over the front of my boots).
Fasa and Tyler mount the Wildcat 108 at ~+2cm from rec.
Fasa (the anti-turner) makes very few turns. I also don't know if I've ever seen Fasa ski switch in the several seasons I have with him as a daily ski partner. Why doesn't Fasa ski on the rec line if all he does is charge forward and (basically) only turn when trees get in the way? Because he rocks a very upright and centered stance, and while he can fold his boot effectively, having the ski engage into the turn with the slightest pressure aids his skiing style. Most of it is fast and straight, but occasionally he needs the ski to
quickly turn left or right a touch.
Tyler (the high diver) skis very aggressively and in a lot of high consequence terrain, but is also a young gun who likes to throw a variety of spins and flips off big cliffs. Moving forward allows him some better air control and flickability for those big lofty threes or dumping 7's off Revy diving boards (see pic below). Now while he would get some help in the aggressive skiing department by being on the rec line, the air control and maneuverability are more important in his ski, because he can muscle through the chop and crud and doesn't need his ski to do as much work for him. The pros of air control and maneuverability are worth the extra leg work when driving through challenging terrain.
Heavier, stiffer ON3P is probably pushing the dense snow around with the tail with more authority at speed, which requires less effort from you. At least that's my guess.
I would be hesitant to move back as you will rely
more on the tail of the ski and I think it will get tougher to move the tail around in dense 3D snow, as it will be more difficult to dump the tip of the ski into the next turn. The tail follows the tip, and if dumping the tip left or right becomes more difficult, the feeling you're experiencing might become more drastic.
You could certainly bump a cm or two forward, but it will cause the ski to engage into the turn much quicker and with a slight abruptness. If it's love in 90% of situations, I would probably stick with the rec line and make minor adjustments in how you ski that exact condition to both keep your skiing style that you enjoy, while making that 10% easier on you.
It will put you in front of the apex of the sidecut and the ski will engage quicker and become more maneuverable. More examples from the team, a lot of us bump the mount on the Commander 108 +2cm from rec, where off piste maneuverability and quickness are preferred to compliment the aggressive and chargy nature of the C108.
On the other hand, most of us mount the Commander 98 on the line, because the quickness and maneuverability isn't as present on the groomers, where we spend most of our time while ripping the C98. Being on the apex of the sidecut and allowing a smooth transition from turn to turn outweigh the quickness from bumping the mount.
Hope all this info helps, hit me up for any clarifications.