"His RMD using last year's table was 20.2. Using the new table is 18.7."

Everything went down, in that the life expectancy increased. What was 18.7 (5.35%) is now 20.2 (4.96%). You might want a reference with both columns, the transition, such as:

https://www.bairdwealth.com/siteassets/pdfs/wealth-management-perspectives/2022-uniform-lifetime-tab...

https://static.fmgsuite.com/media/documents/62a03f4e-4470-466d-ab38-c2d1850bfc7d.pdf

https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-required-minimum-di...