"there is no other historical documentation that would lead us to believe that the film shows 14in shell splashes."
As per all photos and film, there is no historical documentation that allow to time them except (mostly wrong) captions. Antonio Bonomi in 2005 has reconstructed the battle using the available tracks of the ships and putting the photos and the film in the right sequence to cope and support the reconstruction.
During the film analysis it was clear that the Hood explosion scene was added in between the Bismarck firing sequence (possibly for propaganda reasons) but the Bismarck firing sequence is uninterrupted once eliminated the inserted scene.
In case someone wants to state that the shells are from Hood (therefore that the film shows events happening before 6:01), this person must address before the following observations:
Being isolated splashes (not 3 to 5 shells salvos fired every 30 seconds) in a 2+ minutes sequence, being impossible that the splashes are from Hood after 6:01, being Bismarck on a westerly course at the time of the splashes (download/file.php?id=3460) and being the PG turn to starboard (6:04 on her battlemap) well visible at the start of the film (viewtopic.php?f=1&t=8491&start=435#p82759), there is no other logical conclusion than the one they were from PoW local salvos.
I hope it's clear now why the splashes cannot be but PoW splashes fired in local control, not because "A&A" have decided it, but because there is no way to reconstruct (decently) the battle in another way (at least it was never presented here, despite several times requested by "A&A".....).
Worueber man nicht reden kann, soll man schweigen ? no, "Non c'e' peggior sordo di chi non vuol sentire..."