Sorry it's taken me a couple of days, I'm developing.
If you toggle the beta in My Settings, then visit the upload or download test there's an explanation.
There are reasons I originally did it that way and they still hold true. It makes for a more consistent test with far less variables.
Man! Your suggestion for the upload test back in 2018. That's an algorithm I still use. Has saved a lot of bandwidth and time... no joke, over the hundreds of millions of upload tests since, probably something like a decade or more of wait time saved at this point. I can calculate the bandwidth saved... I'll just estimate quickly, going off the recent upload test results
Keep in mind, what's logged to the database is the final result. The client may have cycled though up to 4 tests before getting to the final test.
2 GB in the last 4 minutes (non-peak early morning hours)
1440min per day / 4minutes = 360 * 2GB = 720GB per day
The optimization was made 6 years ago
720*365*6 = 1,576,800 GB or 1.6 Petabytes!
Wow. I think you could easily figure an extra 30+% for the pre-tests. So about 2 PB saved!
Using the current median download speed from the recent download test results of 62 Mbps we can get a rough estimate of the time saved.
byte conversion
62/8 = 7.75 MB/s
2 PB is 2147483648 MB
(2*1024*1024*1024)
2147483648 / 7.75 = 277094664 seconds saved
(((277094664 / 60sec per min) / 60min per hr) / 24hrs per day) / 365days per yr = 8.8 YEARS SAVED!
The actual number is probably much higher. Your post, I'd say has saved at least 10 years of wait time collectively. Amazing.
I'm keeping your histogram idea at the forefront of my mind too. -- I'll post over there.