Nets, Falcon, sorry! As with all of my scripts, if you have a question on how I did something then just ask and I'll respond. Also, dead actor's will not regain SP at the end of battle.
class Scene_Battle
alias shinami_start_phase5 start_phase5
def start_phase5
for i in 0...$game_party.actors.size
unless $game_party.actors[i].dead?
sp_regain = $game_party.actors[i].maxsp * 0.1
$game_party.actors[i].sp += sp_regain.to_i
end#of "unless $game_party.actors[i].dead?"
end#of "for i in 0...$game_party.actors.size"
shinami_start_phase5
end#of aliased "def start_phase5"
end#of class Scene_Battle