Yes, that's correct. Communities under the 09R/27L approaches would see their respite drop from 50% to 25%. The latter figure would also apply to those under the R3 approach.
The often-quoted figure of "33% respite" is a fairly meaningless average of the 50% respite that those under the 09L/27R approach would experience (as at present) and the 25% for the two outer runways.