Correct!
Luckily, nobody may buy a boost which doesn't work...
As for the 4000 XPs, it requires much brainwork to shorten the time with an XP boost economically. Examples were given to max out a one hour boost with two CDP boni.
It's much easier to play 4 days, collect the CDP bonus and get 1000+ XPs for a 9 hole tourney game every day. It will be done on Saturday :) and it will leave you enogh credits to gift a sleeve to a friend.