Just think of "log scaling" as another term for f/stops but applied to time instead of aperture. Add 1 stop = twice the time, add 1/2 a stop = 1.4 times the time etc.
Also, if people want buttons, point them at the
FADU F-Stop Timer android app - it has all the (virtual) buttons anyone could want - across three screens
. Sometimes, simplicity is welcome.