You could, but why? You're essentially throwing away an action to "feel good" about being first in initiative in the next round. Take the example above:
1. Caster wins initiative
2. Delay action until close to the bottom of the round
3. Cast one spell with a partial action and a quickened spell
4. Refocus, probably winning initiative for next round
5. Blast away with standard action spell, haste action spell, and quickened spell.
If the caster acts on his initiative, he casts on the partial action, quickened spell, and casts a spell as his standard action. Repeat at the top of initiative next round.
He's cast 6 spells in his first two rounds acting normally. By refocusing, he's only cast 5, because he had to sacrifice a standard action to refocus.
Now, if he was trying to wait for his opponents to bunch up, there might be a tactical reason to do this -- but he runs the risk of having someone run up and whack him while he's delaying.
Not worth it, IMO. What's the difference between being last in the round, or first in the following round? Nothing, except in the very first round of combat. You're better off delaying until the end of a round if you want to wait a bit, because you don't lose any action that way (review the D&D FAQ, which has an equivalent definition).
