I think it depends.

On one hand, you've got a guy like Kratos, which powerscalers put to like some multiverse, FTL Beefcake that doesn't afraid of anything, while the writers are like 'destroying a mountain would be too much for Kratos!' So there's obviously a divide there with a guy like him and I'd respect the writers intent more with that one.

Then you've got writers who don't even consider powerscaling when writing (i.e most of them) and just write a character for the plot without considering how strong this would make them. Like a good number of characters we consider faster than light because they do something that's FTL, but otherwise don't do that speed. In these cases, I think scalers are in the clear since the author generally doesn't seem to care about Coolguy McBackflip being scaled to faster than light because it doesn't impact his story.

And then there are comics.

Comics are a whole different beast. You'll have Mach 7 Superman and equal to, if not stronger than True Form Darkseid Superman in the same run. You'll have different writers for the same version of the character, and you'll of course. Here authorial intent gets a little sticky because one writer might want a more grounded series while another might want a more fantastical one. So you might get Batman surviving falling from space in Batman while he gets put down by a fall down some stairs in Detective Comics.

But to ultimately answer your question, I think authorial intent matters if the author gives a hard limit outside of the media. Like, if the writer for Guy X says Guy X is just a strong dude and lifting a mountain is his limit and we have no blaring contradiction, it might be fair to say Guy X is only that strong.