Per-word pricing is standard in trade fiction (short form -- e.g. magazine markets, which are mostly dead outside the SF/F genre field).
It's also how I used to be paid as a jobbing IT reviewer/columnist/journalist in the British newsstand computer trade press (caveat: I switched to writing novels full-time in 2005).
It's also how I used to be paid as a jobbing IT reviewer/columnist/journalist in the British newsstand computer trade press (caveat: I switched to writing novels full-time in 2005).