SSPs are in their own 'pool' at Endeavor. They are metered out of their pool based on a minimum/maximum - per class, per year basis. The numbers also fluctuate at times due to staffing at Endeavor. Some folks at Endeavor have sat in their pool for more than 9 months, and as their pool grows it's likely to extend that wait time.

For those with CJO letters, the issue of letter expiration has supposedly been addressed as their pool approaches the time limit. I believe that limit is there to protect Delta in the event of a hiring slowdown and doesn't really do anything for Delta in the Endeavor SSP situation. (just my thoughts)