Eh, to be honest I rarely use supplementary unless Kuchiyose no Jutsu counts (which I bet it does, since there is no attack nor defense involved in that).
Anyway, Bocch, I see where you're coming from but if your opponent is starting off the fight with three S-Rank Techniques fired off simultaneously, which I know is stupid strategy wise, then that starts the battle off in an.... "interesting" way I should say. When Kay said that each turn is six seconds IC wise, then that leaves you with limited reaction time to dodge three techniques. It just isn't fair. Fire off one offensive jutsu at a time. No need to have a backup jutsu already fired and a backup jutsu for the backup jutsu.