Probably not. The LOE is a form letter that is sent by admissions. The one thing that it actually does is authorize an overnight visit.
It seems to me that DS is competitive but not at the top of his slate yet and the RC is telling him he has to improve his test scores. It is common for the RC to give you an idea where you sit on the slate.
I would not sweat having an LOE. Most applicants do not have one and get appointed.
My DD had one her first year and did not get an appointment. She had neither an LOE or LOA her second time and is now a member of 2021.