It’s not the CPI-W that screws you. It’s the methodology. The CPI-W has inflation over 20% since Jan 2021. The last COLA was 3.2%. The dept of SS averages the monthly CPI changes from Q3. If the number were based on the start of Q3 in 2022 and the end of Q3 in 2023, the COLA would have been 3.4%.
Inflation from the start of Q3 2022 to the end of Q3 2023.
July 2022 292.219
Sept 2023 302.257
302.257 - 292.219 = 10.038 10.038/ 292.219 = 3.43%
The 2022 COLA was 8.7% with the averaging. Using the start of Q3 2021 to the end of Q3 2022 inflation was 8.98%.
They are slaving off a few tens each year.
https://www.ssa.gov/oact/cola/latestCOLA.html