The difference I'm referring to the way his shoulders turn past impact. His shoulders doesn't seem to turn fully up to its max limit, unlike Immelman. For me, this shows that he's not into pivot thrust anymore during release. His pivot at that time is just a byproduct of the earlier hip start at Startdown.
The 3 R hands thrust or slap doesn't interfere IMO, in fact I believe it helps release and throw out the shaft from parallel to targetline to inline.
Remember his shoulders turn quite steep during release thru impact, so his pivot doesn't help much in releasing the shaft.
And there's a bonus...he was able to release the shaft with power since 3 R hands is clearly stronger and faster, but also he was able to consistently square the face thru impact bec using the 3 R hands delays face closure.
Look at this -
Young Hogan in the 1st few Swings, 5 Lessons Hogan at around :37, old Hogan at 1:12, in every instance he makes a max rotation of the shoulders in the follow through up to his personal flexibility limit. If Immelman or anyone else goes farther, it's only because they are more flexible.
I don't quite know how to express how 180 degs wrong you are here. The shoulder rotation and lack of any right arm throwing action in the following is clear. The right arm moves at the same rate as the shoulder turn, which is not vertical as you say. You have decided you want to throw through impact and feel it's necessary to justify it by Hogan's Swing - you can certainly throw if you choose, others do it, but you'll have to look for a swing model which isn't cp.