Oops you're right it's not 11% but it's more than 1%. I was charged 154 sats on a 15,000 sat tranfer. The extra 4 threw me I was always better with words than maths.

As for an extra 1 sat.... As far as I can tell WoS has only ever charged me the exact sats I zapped so if you're paying 1 sat or more to zap people on nostr, you're being ripped off 🤷🏽‍♀️