I'm curious about this. I can see how the perceived time would be longer, because after topping it seems like upward growth is stalled while the lower branches fill out, but I'd be interested to find out if there is an actual (as you said) seed to harvest time difference. With all the experiments and comparisons done around here, I wonder if that ones been done? So far I've topped just about all of my autos, but never LST'd one.
To me (as an uneducated new grower) from what I understand autoflowers flower when they're ready. Many people say they have an internal clock for flower, but I wonder if it's more certain conditions need to be met (So much leaf biomass, roots filling a certain space ect)
The only reason I think this is because my first grow flowered 2 weeks earlier than expected (according to the profile on RQS anyway, and I know they're not accurate) so it lead me to believe that the plant had achieved certain conditions and then the ruderalis gene kicked in because it was viable for maturity
So by that logic (again, highly uneducated logic and more than prepared to be told i'm wrong) does topping slow things down entirely? We know a plant would bush out after being topped, but it also put's a lot of focus into healing
Could this "shock" slow root development whilst it's healing and then the other conditions required to be met would therefore take longer, giving more time for the plant to develop in other places before flowering? Allowing a bushier plant but a slower harvest instead of being a kiss of death as was previously believed? Like Ballsack said, it's been disproved that you can't top an auto
All theoretical speculation of course, I'm only on my first grow so have no actual data on this, would be curious to what experienced growers thought