No. The bell note is going to sound at the shortest point
At the risk of seeming to take this personally - I believe I said " some believe that cutting the bell end at an angle can change ..." by which I meant to imply that it is some believe this (and I am pointing no fingers) but I am not one of the some.
Again, the voicing of the bell note on any whistle is determined by the whistle head, not the far end of the whistle.
I would like to suggest to readers to not take any thing read here as the 'gospel truth' but to try your own experiment - "ask your own whistle" and believe what you hear, oh and maybe report back what you find.
What do I mean by "ask your own whistle"?
Well I would refute that the voicing of the bell note is determined by the whistle head and not the far end - and you can try it for yourself and not have to believe me or anyone else. (Note - I am NOT suggesting that the whistle head is not important for the voicing of the bell note, it most definitely is, and unfortunately unless one makes many heads with slight variations or makes an adjustable head one cannot easily test this).
So try changing the size of the opening of the bell by either:
1 - add a piece of tape across the bottom of the whistle and note what happens to the bell note and the octave bell note.
or perhaps to make it easier to hear the difference,
2 - tape the bottom three finger holes to free your hand, and use a finger to partially block the bell - listen to the effect on the spread of the octaves
I am not going to relate what I hear (at least right now) at the risk of influencing anyones experiments
As I finish penning all this I realize I am talking about tuning (mostly) and AvienMael referred to voicing - I usually think of voicing as the 'quality' of the sound, mostly separate from tuning and IMO (similar to AvienMael's I believe) largely (though not totally) determined by the head of the whistle. And I would add that it is the attention to many small details, none of which individually is earth shaking, which ends up making something special