What is the real duration of the Viking's transformation?

According to the in-game tooltip, the official site, and practically every other source the duration of the Viking's transform ability is 3 seconds (either from ground to air or air to ground). However, when transforming a large group of vikings it seems that they don't all finish the transformation at precisely the same instant.

I've read that this divergence is simply created by them moving a little before starting the transformation, for spacing, but upon testing it behaves the same even if I space them in advance. Besides, it happens in the ground to air transformation as well, which doesn't really have any positioning issues.

Is it just a cosmetic effect and the ability does have a constant duration, or does it actually have a random element, just like burrowing has a random element in the duration?

Solution 1:

In Galaxy Data Editor, on the Morph ability for both Viking - Assault Mode and Viking - Fighter Mode, the Random Delay Maximum field is set to 0.5 (seconds). It's just a pre-transform delay for effect :) It also explains the lack of delay on move commands, blink, stim, etc. (they don't have this field set, and in fact may not have it at all)

Solution 2:

While it might be that the 'bumping' causes subtle delays in transforming when landing, you seem to have controlled for that. An only tangentally-related issue is when you command several to land at a time in a small space, is that some won't at all because it's too crowded.

The nominal transform duration is 3 game seconds, which is about 2.2 real seconds on "Fastest", however there is a small degree of variance beyond just the animation. This is readily apparent if you give the vikings a move command while transforming, into either air or land mode as some will set off before others. Additionally, it doesn't seem deterministic as far as where the unit's selected in a control group—the first to transform one time won't always be the next—so it is possibly random.