I know the final answer will never be shared by the devs and probably it is some strange formula with a lot of coefficients and as far from linear as possible.
However, I think that collecting feedbacks from everyone can help in figuring out at least some general facts.
I always do the challenge event in a hurry so I never had the time to track the single scores and correlate them with different tactics, but once I tried to do as much combos and matches as possible to test the following idea:
does the combo/match score increase for each “big” combo or “big” match (where big means whatever, e.g. >3 combos, >5 tiles match)?
since the time bonus decreases to 0, there is a maximum time passed which you don’t lose anything for playing over (you just get 0 you don’t get negative time score). So if the hypothesis under test is true you can keep collecting big combos and big matches, and eventually the combo/match score will make up for the lost time bonus and any new big combo/match will give you a further edge.
Perfect, I made a one color team with the color reflected by the enemy, just heal and kill by tools when you think you’ve had enough of this.
despite having done really a lot of really big combos I got one of my worst results for that level.
the hypothesis under test should be false, so either the combo/match score is based on the best combo you can do (so unless you do a 50 combo you don’t repay for the time score) or it is based on some average, so even if I did a lot of 10+ combos they were averaged out by the countless 2 combo or no combo matches I did.
Don’t you think that putting together all of the tests and observations anyone has made we can try to figure out a general rule, or at least some further tests to put in place to sort things out?