Above 8 weeks (10 for shiftworkers) the employer and employee may confer; if agreement fails the employer may direct leave in writing within the limits (6-week floor, periods of at least a week, starting 8 weeks to 12 months ahead, consistent with agreements), and an employee with excess leave for over 6 months may by written notice require leave within the same limits (up to 4 weeks, or 5 for shiftworkers, in 12 months), which the employer must grant.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.