Totals add as stats, and though it might not be exactly fair (sonic has X about of bosses so each of his boss ranks count as 1+1/X), it's still the same for everyone...
just X is 1 if they only have one boss, essentially making it too...
Also, the fewer bosses that are had to a character, the less fierce, in general, that competition is... I see no real reason to change it, as it would then be unfair to have totals at all... and I likes me totals...