>how did pushing the interim back help the final alpha allocation? It should have hurt it.<
Even DNDN concedes that the alpha for the final analysis and the power of the final analysis are lower under the new SPA than under the old SPA. The only question is how much lower.
The alpha of the final analysis has not been disclosed under either the old SPA or the new SPA but the power of the final has been: according to DNDN, it dropped from 90% to 88%.
Some posters (e.g. ocyan) take these numbers at close to face value while other posters (e.g. iwfal and I) think the SPA change was more injurious to 9902b’s chances than DNDN is letting on.