Its an aggregate of tests.. More often than not, when you think you haven't done well, you end up doing good. All you can do is wait and hope for the best. Just messing up one does not put you at a disadvantage if you've done relatively well in the rest. These tests are just to see that you match up to the hand eye co-ordination needed to fly airplanes and if you can react quickly to changes. These are required for instrument flying skills. The memory tests are to check your retention power for clearances and read back of numbers and not to forget checklists and procedures.
Good Luck
