The sizable damage bonus is applicable as long as the Hit Streak number is red, and the sword is glowing. Once the charge(s) are expended by performing a special move (such as an Execution or Wraith Blast), the bonus does not apply until the Hit Streak is charged again.
At mid to high Hit Streak levels (15+ and 30+ respectively), the damage from a single well-timed Flame of Vengeance-enhanced Critical Strike can slay normal Uruk in a single hit, and at high streaks will also shatter Defender shields and utterly bypass the Berserker's ability to Counter Talion. So when the streak is high and charged, it is often expedient to use chains of sword strikes to quickly kill large groups, instead of consuming the charge to perform an Execution.
Blade Master • Brace of Daggers • Brutalize • Critical Strike • Critical Strike 2 • Death Threat • Double Charge • Execution • Flame of Vengeance • Impact • Last Chance Finisher • Poison • Resilience • Shoulder Charge • Strike from Above • Swift Finisher • Throwing Daggers • Vault Stun
Brand • Caragor Hunter • Combat Drain • Detonate • Dispatch • Domination • Elven Swiftness • Fire Arrow • Graug Hunter • Lethal Shadow Strike • Pin In Place • Quick Draw • Ride Caragors • Shadow Mount • Shadow Strike • Shadow Strike Chain • Stealth Drain • Wraith Blast • Wraith Burn • Wraith Finisher • Wraith Flash • Wraith Stun