[jlg23]

> If you finish early, there is usually nothing stopping you from helping out with other miscellaneous things than just the big projects.

From an employees perspective: Then what is the motivation to perform better than my peers? More work than my colleagues and the hope to get a bigger bonus?

If someone is performing better and helping out in the remaining 3h, do you also pay extra for these 3h? If not, ain't it wiser for the employee to finish the work in 7h and help out for 1h? Less overall work, same money and one still stands out as a performer.