I believe a parallel command won't run until the sequential command above it has finished. if you want two things to happen simultaneously, make the first one parallel.
This is a snippet of our code from last year:
Code:
addSequential(new ShootAndReloadBall());
addSequential(new WaitCommand(0.75));
addParallel(new IntakeFastStore());
addParallel(new DriveStraight(DRIVE_SPEED, DRIVE_TIME));
The last two commands execute at the same time.