The song played was Me Gustas Tu (I Like You) by GFriend.
Yes, V24 is typically 15 to 30 Hz low. This is actually the best way to detect the 4900 kHz transmissions since the broadcast station moved onto that frequency. When V24 is too weak to hear over the BC station you can always detect the carrier being slightly off form the BC station carrier. Fortunately V24 is often about he same strength or stronger than the BC station for me.
T!