Here’s a link to a similar post where the question states exact language from their contract regarding the look back period. https://mycomplianceresource.com/forums/topic/regulation-z-arm-notices/
Loans made prior to January 10, 2015 with look backs of less than 45 days can continue to send the notice 25 days before. So if you have loan programs with short or no look back period make sure you update those programs in time to be effective 1-10-15.