i would say what this means is that your plants are getting a lot of light and dont feel the need to stretch. personally, i keep my lights close enough that when my plants went into 12/12 they were only about 6-8" tall, from seed. they hardly ever stretched due to good light, and when i went into flower i decided that they would need a bit more height if i wanted them to yield well. moving the light away (went from 3-4" to 6-8" distance) and i got a good 2-3 inches over the next few days.
when you say putting the plant on the far side of the tent makes them stretch faster, it furthers my opinion. move your light a bit farther away, and you will promote their stretching. get them close to where you want them, then move that sucker right back!