The organization I work for is CMMi L3. For maintenance projects, we currently use a parametric method to estimate size, complexity and effort. We have implemented improvements to this technique, but still, there is large variability on the performance of this method (when compared against actual effort, which we record).

There are strong initiatives to move to a more agile approach, including effort estimation using planning poker, but we don´t want it to turn into a total-guessing and whole-dependable-on-persons technique

I understand that (out of the box) it covers PP, because attributes (size, complexity) are estimated, and later effort get derived from them

However I´d like your comments on maturity level 3 practices, such as Generic Pratice GP 3.2 (Collect Process Related Experiences), IPM SP 1.2 (Use Organizational Process Assets for Planning Project Activities)

Thanks for your comments
Juan Carlos