Not quite sure what you are asking. Marriott has published that rollover nights will be in place from 2012 to 2013. They have not said anything going past those years.

A couple of other points.

1. Rollover nights do not rollover themselves. Only actual stays, CC, and promo nights do.
2. If you rolled over 100 nights this year, you instantly had Platinum. However to rollover any to next year (at plat level), you need 175 nights. 100 rollover plus 75 other nights.

I don't know how you can predict Plat until 2015. If you didn't rollover any this year, you will rollover 45 into 2013. (120-75) You will need 30 nights next year to maintain plat. into 2014 and 120 nights to begin rolling over to 2014-if they continue rollover.

I am sure that can be explained better! Its a little confusing.