Multi-note Tremolos confusion and xml import difference

I got this to work, but getting there was confusing.
This is the measure in Sib:
Screen Shot 2024-04-06 at 6.08.00 PM

Dorico imported the XML incorrectly (not sure why it didn’t import; but, it did, although other multi-note tremolos were okay, maybe it was the “presumably invalid” duration of the bar which Dorico attempted to “correct”?), as:
Screen Shot 2024-04-06 at 6.09.25 PM

So attempting to correct this, using force duration, is just strange, as: first, they have to be force-entered as dotted-quarters (not dotted-half: confusing):
Screen Shot 2024-04-06 at 6.12.39 PM

second, then use Repeat popup, 22 (that part is straightforward), to magically transform these into not only the desired tremolo, but the desired forced-duration (confusing):

Screen Shot 2024-04-06 at 6.14.02 PM

So, the Dorico result is as-desired, but, I don’t know if there is a better way which could be used instead, enter this?

My first attempts (before figuring this out) was to try various normal rhythms (not force duration) then extend-duration either of these notes; but, this also removes the tremolo (which, I’m not sure why changing the duration of one of the tremolo notes would remove the tremolo, maybe it makes sense, or maybe not).

Well illustrated. This exact tremolo issue has been brought up here in the forum over 30 times now. No, there isn’t currently a better way to get it done.

BTW, what you call “confusing” is the way it works in both Sib and Dorico. Standard tremolo notation is that both notes are the full duration, with the first one on the first beat and the second halfway through. (I suppose the notation might also be clear if the second note didn’t have to be so far to the right, but this is standard.)

What might be preferable is to handle it the same as hemiolas (triplets) or trill regions. If it had a region length then it would be simple to drag the tremolo over multiple notes; or, if it were handled as if under a (perhaps invisble) bracket which automatically force-durationed all notes underneath it, to the specific duration (just as triplets kind of do) - then, the “illegal length of the bar” problem would be resolved.

I refuse to learn Sib after having experiencing it briefly years ago, so I’m not much interested in having the ‘operation’ of it be similar.

In Guitar Pro, these types of “different duration than standard” notes are handled by being underneath a note modifier, for example GP handles the triplet by allowing the composer to mark any note or any duration as a “3” note (or any n:m count) and surrounding notes with the same marking, are automatically “grouped into the hemiola” together. It takes care of the grouping immediately so it is possible to see the bar beat-count being complete or incomplete.