If I understand what those nodes actually do .. is they increase the % chance of them throwing those specials ... so they don't necessarily (?citation needed :P hehe) decrease the % chance of other specials .. In short, with those 2 nodes, he'll be very likely to throw sp1 .. however, if you get him to sp2 .. he'll be very likely to throw it as well.(I reserve the right to be completely wrong .. :P )