My advice Capn:
Never go with the combo unless the combo calls for you to go. They aren't reading your mind, and aren't expecting to have to uber you, decent chance you or your pocket will die in a trap or get dropped if you are showing up uninvited to the uber party. So either ask to come, or listen for the "scout come with us", "we have uber adv, we are pushing" call. Otherwise just wait until you hear confirmation that your combo has indeed pushed into fighting position, popped, trading ubers, listen for your combos call on where to collapse/who might be lit and if the uber is better or worse. For the most part if your combo is not saying these things to you, then a lot of your work is guesswork and it is tough on the flank in general, so don't think the problem is all you. It's a team game, communication beats DM a lot of the time.
As for scout, try hard never to die "too soon". Scouts best class at end of fight, be alive at end of fight.
And as for your off uber push, if you guys are doing that, make sure you have a buff and you are mgelord, work with your scout buddy, 2 v 1 is better then 1 v 1, call a focus and bring a friend. Lastly, if that 1 v 1 fight isn't looking advantageous for you, just fricken leave, you are a scout.