IWG RD-ASEP status report to GRBP-83 after the 10th session in December 2025. Work on RD-ASEP for UN R51 is developing a mandatory procedure after the monitoring phase, while R41 work has concluded. The Data Analysis Task Force reported on database sufficiency, boundary conditions, CVT vehicle modelling, and potential inclusion of N₂/N₃/M₂/M₃ vehicles. An Editing Task Force created a consolidated R51.04 draft reviewed in December. IWG RD-ASEP recommends no monitoring requirements be approved without corresponding mechanisms to collect, analyze, and report results. M category/R51 informal document submission expected September 2026 and working document February 2027. L-category/R41 requires no further action.