March 2nd, 2012 8:39pm
Yes, and I believe a lot of players do it. Don't expect more than a few tenths or half a point, though, because by that point in the season any staff you add are only going to contribute a fraction of a percent of the total caption.
For example, let's say that going into Finals your Musical Ensemble and Musical GE skill values are both at 10,000. Then you purchase two ranks of Winds Arranger in your staff (+150 Mus Ens, +150 Mus GE each rank). You've added 300 more points to each caption in skill, but that's an increase of only 3% over the 10,000 you already had. And the percentages are not a direct correlation (because you increase the caption value 3% does not mean your score in that caption will rise 3%).