Nothing precludes you from upping the TTL after the change. Traditionally DNS admins progressively drop the TTL prior to a change to reduce the time an RRSet is

Nothing precludes you from upping the TTL after the change. Traditionally DNS admins progressively drop the TTL prior to a change to reduce the time an RRSet is in flux (so if your TTL is N, N + 1 seconds prior you drop it to half N, and again and again until its your preferred window size) and cautious ones slowly ramp back up again to the regular value.