This study was based only on the self-reported statistics by the participating SART clinics; available on the SART Web site. It is no surprise that frozen are somewhat less successful; these statistics have always been clear, although they are improving.
Still, frozen offers a number of advantages over fresh, such as the elimination of cycle synchronization (which can be difficult for the donor and recipient to coordinate); indeed, there is a lower cycle cancellation rate with frozen eggs. In some cases, frozen eggs cost less than fresh cycles.
At Northeast Assisted Fertility Group, we have a selection of frozen eggs from donors who have donated successfully in the past, and offer them in larger batch sizes (than the typical frozen egg bank offers). This mitigates the risks. These factors were not taken into account in the study.