The Max Impact values (full length of the bars) are the theoretical maximum points you could have earned with a valid team composition without using chips if you picked perfectly. This includes a single DRS Boosted driver (x2) and doesn't take into account any budget restrictions. A well played x3 chip could result in an impact score that's higher than the Max Impact score.

The Max Impact values (full length of the bars) don't include points from potential multipliers (x2 or x3) on drivers. Therefore it is possible that - if you're really unlucky - your impact value is actually higher than the Max Impact value.