Accelerating expansion and isotropic sky-hemisphere consistency in Pantheon+ supernovae: a revised analysis in the dark energy debate

We perform four independent decompositions of the deceleration parameter q 0 using 1564 Type Ia supernovae (SNe Ia) from the Pantheon+ catalogue: by redshift bin, sky hemisphere, host galaxy mass, and supernova colour, correcting a coordinate error identified by Sah, Rameez & Sarkar (SRS26) in the sky-hemisphere direction used in our original analysis. Without any progenitor-age correction, the full sample yields q m=-0.490, consistent with the CDM expectation of-0.55. Applying the Son et al. (S25) progenitor-age correction shifts this to q m=-0.267, remaining in the accelerating regime. The sky hemisphere test, using the corrected CMB dipole direction (RA =167.80, Dec =-7.10), shows consistent results between the CMB dipole (q m=-0.527) and anti-dipole (q m=-0.464) hemispheres, supporting isotropy but not the strong deceleration values reported previously. Our revised results are consistent with and do not support either the original claim of near-zero baseline acceleration or the S25/SRS26 claim of a decelerating universe.