Yes. Getting a mate-in-one wrong will usually net you a huge loss as compared to getting wrong a Carlsen-like position.
Tactics trainer on the phone
The time is really essential when you're using Tactics Trainer. You're getting compared towards the other people that have tried to solve the same puzzle and if the average person is solving it fast and you're not able to do the same, you will lose a lot of points.
You should play with the timer option available, then you've concrete idea how complicated the puzzle is. If the timer is low then it's an easy maneuver and if the timer have a lot of time the position is probably complex, so you should spend some more time to calculate different variations more closely.
Why is it always so negative to our ratings? Whenever i get something wrong, i lose about 25 points. Get it right and im lucky to get 7 or 8, even if i get it immediately... what gives?