You can nudge and tease yourself quite close as opposed to the standard deceleration process..
I know about that one since a long while already, but with my sluggish ASP am I most of the time losing all I gained on finding the damn thing again, then 75%ing the remaining distance which not rarely makes it seem like even MORE wasted time.
Which all in all shows to me even better how fricking annoying SC is.
Going a bit off-topic, but I would be less annoyed by supercruise if it displayed a real estimated timer taking your acceleration / decelration rate into account. It's a minor thing for me, and I still like travelling around (even though the supercruise sound kinda annoys me after hundreds of hours), but I really don't find the whole "wait for 0:07 to display - decel - stay at 0:07 for 30 seconds" mechanic... let's say... future-proof.
I've thought about this often too and you're right, nothing is worse than it going "you'll be there in 5min, but I will decelerate now and it will go down by 1 second every 5 seconds, have fun", except that you'd lose the ability to go 100% most of the time and then cut it back to 75% at 7-6 sec ETA, which is the braking limit of SC.
Then again, that would also not be an issue if the TOO FAST warning would show up BEFORE it's too late to brake in the first place. If that thing shows up at 10sec current ETA then you'd have 3sec to cut back and still not overshoot.
These things about SC annoy the hell out of me since before the game went out of beta, only that back then with the small actually usable bubble it wasn't that much of an issue as you had not a lot to go to, and I've brought these things up a couple of times every now and then again since then, and I am still waiting for things to change

The closest that was even hinting at them changing were the rumors about in-system jumping, which might or might not become a thing, somewhen (tm).
I swear 90% of my 7w ingame time are spent on straight line SC... Feels atleast like that.