Page 390 says it isn't REQUIRED until 150K miles, but it is supposed to be done every 30K if you PRIMARILY (not occasionally) either:
- Tow a trailer or use a car top carrier or camper
- Extensive Idling or commercial use
- Dusty Conditions or unpaved roads
It's a sealed unit, so it's similar to manual transmission fluid change intervals (which I think were around 75-125K miles for most cars, but most people ignored).
$200 seems reasonable, but I wouldn't really want anyone opening up the system. If it were my car, I might think about it at 100K or 125K rather than 150K, but there's a good chance I'd just run it to 150K miles.
The dealers like to sell fuel injector cleaning also ...