One of the inputs for Plan Risk management is cost management plan.In PMBOK page 277 this is shown
as an output of Project cost management. Contrary to that in page 165 the PMBOK says that the project cost
management plan is developed in the Develop PMP process. 

Why this confusion and which is correct?

Also the cost, scope and schedule managment plan are developed during the Develop Proj Mngmt Plan process.