This report serves as an addendum to the report 2015 Eastern Interconnect Baselining and Analysis Report (Amidan, Follum, and Freeman, 2015). This addendum report investigates the following: the impact of shorter record lengths and of adding a daily regularization term to the date/time models for angle pair measurements, additional development of a method to monitor the trend in phase angle pairs, the effect of changing the length of time to determine a baseline, when calculating atypical events, and a comparison between quantitatively discovered atypical events and actual events.