Does the Permanet Mana Bonus on Mana Flow Band Apply to Bard’s W?

^ His w is by far the highest mana hungry spell in his kit and I always wait for mana flow band to come back up before I cast it. Will the 15+ permanent mana still be given to Bard even if his heal is delayed?

For those who don’t know: [New Effect] "If the ability damages an enemy or aids an ally, permanently gain 15 mana."