411A, you used 5%? I'm surprised! Its been 10% since 1991.
I left in 1990, Mutt, so it might well have changed after that.
Up until then, it was 5% with a standard release, which could be reduced to not below 3% with a re-release, which was always used inbound to home base.
Generally never a problem, as the fuel burns were quite generous, and took into account performance penalties with older aircraft.