I understood it to be same type of spell. Hence, you could mix two destruction spells, for example.
yes that would make more sense. but its not very interesting if we, say, combine a fireball with an ice bolt, and all we can is a new spell with both effects. i hope they come up with some new nice effects or whatever.
and.. maybe im not thinking clearly, but i cant imagine alot of spell types that could be combined at all :shrug:
edit: read the article again, and it really says "or put the same spell in both hands, to combine the spells for extraordinary effect". so
the same spell sounds alot like the same spell, not just only the same type of spell