It is indeed possible to charge your EV with a level 1 charger running at 16 amps using a NEMA 5-20 outlet. You'll get a maximum charge rate of 1.92 kw/hr rather than 1.44 kw/hr, which is at least 25% faster.
I really dislike "pamphlets" as product manuals. I've seen ladder racks with 30 pages for a manual. With as little information as the "pamphlet" has, just put it on stickers on the side of the charger.