Wrong basically. Plants reach a maximum height for their strain. The legendary "stretch" is exaggerated when you veg for just 2-3 weeks and then flip to 12/12. Since the plant is still not max height it then works like mad to get to that height like a human maturing. If you veg them 3 months and they reach the 60 CM advertised by the breeder they can sure stretch longer - but most likely any stretch will be very small.
No, it wasn't wrong. What you said isn't applicable to indoor growing at all. I've never seen a strain advertised that reaches a max height of 60cm, that's less than 2 ft, (maybe autos but those don't apply when talking about how long to veg for how much stretch).
I do however see plenty of breeders saying "expect 2x or 3x stretch". Because they know that no one is gonna veg them until they stop growing vertically,that would be a waste of time and electricity. Unless you are doing scrog/ lst, most growers plan on them doubling (or more) in height and flip to 12/12 accordingly.
You said that the "legendary"? stretch only happens when plants have been vegged a short time like 2 or 3 weeks, but If they have been topped multiple times and tied down (like the OP said he did) for 2 or 3 months and then flowered,they will still more than likely double in height. Because,using your own logic..the max height hasnt been reached. There is a max height,but not a max amount of growth.
The amount of veg time doesnt matter if the height hasnt been reached, and with all the hybrids people grow today,thats rarely gonna happen indoors