In an unexpected move (although all-too-common for an increasingly erratic agency), the USCIS will no longer accept Premium Processing Service (PPS) for all H-1Bs, except for H-1B extensions with the same employer or H-1Bs for cap-exempt institutions, such as Universities or research organizations.
Effective September 11, 2018, PPS will not be available for H-1B cap petitions and H-1B amendments. The ban on PPS will continue until February 19, 2019.
The justification for the ban on PPS is to reduce overall H-1B processing times.
If you are asking yourself how eliminating a fee-based premium processing service will reduce processing times, you are not alone. The PPS is supposed to pay for itself. This is yet another example of an agency that cannot get out of its own way.