Taking into consideration the fact that the percentage of people likely to put in the time to explore documentation and settings and discover the original configurability is probably quite small, and a reasonable assumption that not everyone who discovers the functionality will use it, yeah, the number sounds all right.

Note, btw, that the number they seem to be going for is the above -- e.g., "according to the accounts database, only 3% of users ever changed this setting", _not_ "only 3% of users are claiming to care about this now that it's been removed".