Does the Orb of Imposition's alternative effect affect more than one creature?

Question

Does the alternative effect of a wizard's Orb of Imposition [ddi], i.e. the extension of a duration, also only affect one creature?

A player is wondering if the Slow effect of Stone Blood [ddi] could be extended for all the creatures in the burst.

Effect: You can use your orb to gain one of the following two effects.

You can designate one creature you have cast a wizard spell upon that has an effect that lasts until the subject succeeds on a saving throw. That creature takes a penalty to its next saving throw against that effect equal to your Wisdom modifier.

Alternatively, you can choose to extend the duration of an effect created by a wizard at-will spell (such as cloud of daggers or ray of frost) that would otherwise end at the end of your current turn. The effect instead ends at the end of your next turn.

And Stone Blood:

At-Will Arcane, Implement, Transmutation
Standard Action Area burst 1 within 10 squares
Target: Each creature in the burst
Attack: Intelligence vs. Fortitude
Hit: 1d6 + Intelligence modifier damage, and the target is slowed until the end of your next turn.

Answer 1

Yes.

Of course, because of no saving throw is involved we are talking about the second option of Orb of Imposition.

Stone Blood is a Wizard at-will power, so it is a viable choice. It also has an effect that lasts until the end of the caster's next turn. In this case the effect is to slow every creature hit by the power.

It is a de facto enhanced version of Ray of Frost (with the exception of damage and school keywords and the possibility for friendly fire) which is explicitly listed as a viable choice in the Orb of Imposition text.

Answer 2

As it seems, nothing in the game text restricts the effect to one creature.