Chill,
I am NOT the expert, but here's what I've learned from my reading:
In general Lead loads are lower than Jacketed as the lead requires less pressure to obturate and seal the barrel and thus generate xx velocity from a given charge for a given bullet weight when compared to Jacketed.
Maybe not all powder/ load data companies show that, but most do.
Plated occupies that middle ground between lead and Jacketed and depending on the manufacturer/load data they will recommend using lead data or up to mid level jacket data. More and more powder and bullet companies are generating/publishing load data for the plated, so it's something to check.
As to the bullet shapes/profiles/lengths, those all will have an effect on seating depth, COAL and of course charge weights.
That wide difference in the Titegroup data you have there is interesting, but remember that different sources will often have a wide range for loads. As always -- work it up - test it and see how it works.
As to Alliant showing the same load for a powder and Lead/Jacketed bullets -- that is a little uncommon, based on what I've seen. Now, something to keep in mind is that general Alliant lists the max load and you have to scale back 10% and work up from there.
As to how it relates to WST -- here's what I did -- YMMV and all that other important stuff --- I found some old data from Winchester on 9MM and WST, I found the recommendations on the Brian Enos forums, I had some feedback from other THR members, then I determined a range to test for my uses -- 4.0 - 5.0 grs. under a 124gr Berry's RN. I fired 10 rounds each at .2 gr increments from 4.0 to 5.0. I judged the recoil, ejection, cycling, function of the gun, inspected the brass and was satisfied. I then decided to use 4.3 as the load starting point as it was towards the bottom and was functioning fine. I did load some up to 4.4gr to help cycle my Glock 34 better. I then loaded up some of the Berry's Hollow Base RN Thick Plate and bumped some up to 4.5 given the "extra" case capacity and smoother cycling of the G34.
When I switched to lead bullets I kept it at the plated load levels as they generate similar pressure levels and note the information above - plated uses lead data.
On the subject of bullet styles, profiles and such -- this will affect the seating depth and for me, that's a matter of using the Plunk Test. One thing I've noticed is that when loading lead bullets, I have to adjust the seating depth/OAL to ensure a good fit in the chamber, particularly in the Lone Wolf barrel for the Glock 17.
I hope this long-winded answer helps, but remember that's why we work up loads.