I hear you. That's my one complaint on my Level.2. I ride it 90% of the time on PAS1, and it's hard to go slower than 15 mph. I told them about it; they said they'd forward that to the engineers.
On the other hand, when I turned the PAS off, I found myself going 13 mph on my own energy alone, so maybe I got stronger than I realized or the bike just rolls that efficiently.