According to numerous articles in R&R & elsewhere, PPM is not kind to the SJ format, which is a TSL-driven format; that's why you've seen several new top 40 stations launched in LA, NYC, SLC, Denver, San Francisco & Las Vegas within the past 60 days.
KLSX/LA flipped from a talk station with Adam Carola & Tom Leykis among others to CHR/Pop on Feb. 20th, and has soared from a 1.5 to a 3.7 rating in three months, and beat heritage CHR/Pop monolith in 18-34 in the process.
Also, KIFM/SD has been #1 several times over the years, frequently with shares of 5.0 or even higher.