You would not believe how unorganized the automakers are, which makes accurately predicting anything pretty tough. For example, the F150 plant in Dearborn works four 10 hour days to avoid paying ot because they allowed them to take ot after 8 hrs out of their contract. They have decided its a good idea to only have enough parts to run as they use them and no surplus on hand for assembly. The plant regularly runs out of parts due to various reasons and they stand there getting paid to do nothing or get sent home with a minimum amount of pay no matter how long they were there. If it happens enough they have to work the 5th day on ot to make it up. The examples go on and on.