Does a light fourth seat opening work on the same principle as fourth seat "balancing?"
It is critical when opening in Fourth Seat to make a plus on the hand - you have passed a simple opportunity to score zero, so should have a good reason to believe opponents cannot outbid you or set you. If holding less than full values you must have both length and strength in the Major suits.  This is an excellent (light) fourth-seat opening of 1S (even playing 5-card majors)

S: KJT3
H: QT6
D: A842
C: 52


and this is a very poor (light) fourth-seat opening of 1D:

S: 52
H: QT6
D: KJT3
C: A842


It is also important to be playing some agreement such as Drury raises that allows partner to show limit-or-better support at the two-level, in case you are light.

Update - Further to @ruds' mention of Casino Count, in order to open  in Fourth Seat one should have a reason to believe that one has the best hand at the table. Otherwise, someone else's hand is better than yours, and you are no longer favoured to get a plus from opening. Holding length in the Majors, and especially Spades, is often the slight edge one is looking for to achieve this belief.