What was it that Jonwilly said?.....
I have never hears so much Sh1t talked about a subject as this one
Max contingency check
is a power assurance check. It's to assure the engine can be worked at max power, keeping Nr in limits, without being limited by temperature or N1.
PPI provides a trend to monitor the condition of the engine, and bring to the attention of the operator any deterioration in it's performance. That's why you've got that page in the M700 to plot and record the figures on a graph.