I don't know who to thank for TryAPL. The community at large? This was the first link in the help on that page that seemed like I could quickly send off a message. I haven't crossed the APL event horizon, but I'm slowing being drawn in. I... I think I'm okay with that.
grade up instead of grade down: {⍵[n,⍨⍋¯1(⊢+*)⍳¯1+n←≢⍵]} (The grade could probably be replaced, it just increases every value - except the last for odd inputs - by 1)