I don’t know why, but movies seemed better at old age makeup in the 20th century than it does today.
http://boredbug.com/hollywood-old-age-makeup-is-spot-on/
This is supposed to be the ROTS Tarkin makeup test, and it looks better than what was in the movie!
In any case, it’s been 11 years since ROTS was shot, so it’s not like they need to do much to age Smits another 9 years.