Mythic + Key time decay score ratio

I’m trying to figure out how mythic + scores are calculated based on the time. So example:

Say I was running a +17 key. If you time the key exactly on time, it’s 202.5 score if it’s your best time of either tyrannical/fortified affix. However, say I did the same key and missed timing it by 2:30 seconds… what would the rate of time decay be on that score?

Does anyone know the rate of decay after a key time is missed?

Just trying to make a fun spreadsheet for people to calculate their future scores. I know that raider io does all these already I just want a tool I can use to figure out what keys to push that are better to do so on and still manage a 2000 score.

Missing the timer is instantly -10 (I missed one by 4s this week). 40% over is “grossly out of time” and rewards nothing. Based on some of the stuff I’ve read, you can get up to -7.5 between 1s and 40% of the timer.

The rate of decay would be based on the timer for the dungeon or you could just set the out of time at 0.1% and scale it to 40% to make it easy.

I missed one by 7.9 seconds which equates to .3%. I’m just having a hard time determining what drives the final score because it seems like every key’s a little different.

Is that % based on the overall time like mists is 30 mins and then based on the time over of percent of that time? Or is it an actual formula they use.

My head hurts so much from trying to figure this all out.

" In addition, you can receive a Time bonus or penalty depending on how fast or slow you complete the keystone. Here’s what we speculate:

  • You can earn up to 7.5 points by being up to 40% faster than the keystone timer.

  • You can lose up to 15 points by being up to 40% slower than the keystone timer.

  • Keystones that are massively over the timer will award 0 score."

https://www.wowhead.com/guides/blizzard-mythic-plus-rating-score-in-game

I was a little off.