Isshin Shorinji Ryu System is a modification of the Isshinryu system created by an instructor/group in New Jersey.
As in all cases they make the claim they've prepared a stronger system. Journal of Asian Martial Arts (JAMA) ran one of their articles about a year ago.
Going solely from memory, their additions were not of Okinawan origin, and their validity would require seeing not reading, IMO.
For their claims, you either believe it or not.
bushi no te isshinryu