Depending on your speed, a fast line through the first U turn would not perform a full 180. Say you started the marked path from stopped. By trying to go in a straight path from the inside wall of the first turn to the inside wall of the second, you could cut as much as 30 degrees of actual turning. If it were a fast approach, one might need to start wide, come out centered to approach the second turn, and then the total amount of turn would be okay.
(Edit: If you are coming from a direction that adds a few degrees of turn before entering the road block, you're probably fine)
Turns more than 180 are totally okay. The range between 45 and 179 is all that is excluded for this contest.