Epic Spells

I've noticed a few times that epic spells seem to be getting 2 uses per day insteaad of 1. Is that as intended? And is there any specific requirements to get that second cast? (Like more Spellcraft above the required amount to get the feat or some such)

Only two current epic spells have had an extra cast added.

Hellball, and Greater Ruin.

This was done because these two spells are the "big epic reward" attack spells that an epic caster gets for investing all those levels, skillpoints and feats.... and getting one use per day frankly sucked majorly... against epic level enemies, one cast of each barely makes a dent most times... two casts is not much better, but still a significant improvement.

There is no additional requirement for the extra casts. Grab either of those epic spell feats, and you get 2 casts/day.