I was under the impression (apparently mistakenly) that having multiple barracks of a level capable of training a given troop would allow you to spread the training around. For example, if I have a troop who requires a level 6 barracks to train, and my barracks are levels
7 6 5 4, then it will train twice as fast. If I instead trained a troop who required level 5, it would train 3x as fast since I have 3 barracks to train them at.
However, I experimented with this and it had no effect. I am unable to empirically determine any pattern (or for that matter, even notice a difference) in training speed as a result of having multiple barracks. My attempts to search for such a formula has proved unfruitful.
What is the formula for determining training speed?
(I'm playing Battle for the North if that makes a difference - there wasn't a tag for it, and I'm not experienced enough in the game to know if there's a difference between the two!)