Phase II is not one event. Before the peak the whole mass is held at 45 to 52 °C for about two days. ICAR-DMR calls this pre-pasteurisation conditioning, or PPC. Its job is to grow the thermophilic flora, the heat loving bacteria and actinomycetes that later do the ammonia work.
After pasteurisation the compost is brought down at about 1.5 °C per hour and held at 45 to 48 °C. This is post-pasteurisation conditioning, or POPC. DMR gives 3 to 4 days for a bulk tunnel above 15 tonnes, and 4 to 5 days for a smaller one, or as long as the ammonia takes.