Does the amount of time left determine how many points I get or does it not matter as long as it hasn't expired yet?
I do believe that the more time you spend solving a tactic, the less points you get. (even negative points for taking too long)
Yeah, and it's silly IMO. But that's why I prefer chess tempo, despite being less polished.
I just did one that started with 20+ min which seemed like overkill but I only got 8 points after doing it in one minute with a rating
It also depends on the rating of the problem vs your rating.
Does the amount of time left determine how many points I get or does it not matter as long as it hasn't expired yet?