The AP discounts are much narrower. Offered only at a few restaurants, within the parks it's usually only for lunch on weekdays, and alcoholic beverages are not included in the discount.
Two in-park restaurants that don't take TIW, Teppan Edo and Yak & Yeti, do have an AP discount - Teppan Edo 10% off lunch on weekdays, not including alcohol, and Yak & Yeti 10% off on entrees only.
TIW is 20% off the full bill, including alcohol, at participating restaurants. Most TS restaurants and a few CS participate.