Also, isn't an entropy difference of 0.32JK-1 not that large, or in terms of entropy is that significant?

Again as in 27.5 Penrose's Emperors New Mind p313 is useful. With Boltzmann's k.logV
the log makes very large numbers manageable. The natural log of 1billion (10**9) is only 20.7, and Boltzmann's constant k is very small: 10**-23 joules per degree Kelvin!
Also while the phase space volumes are multiplicative for two independent systems the log in Boltmann's formula makes entropy conveniently additive. The old sliderule (perhaps most readers are not old enough to remember them, to say nothing of log tables, long before pocket calculators became the vogue) uses logaritmic scale to convert multiplication to the simple addition. Another place where a logarithmic scale is used is the decibels used to measure sound intensity, as our eardrums apear to use a logarithmic scale!
Les