The shorter tower will produce a different level of interference. Even with less power, it may produce more interference to near-by neighbors.
I went through this when we replaced the towers at (then) WQYK-AM, Seffner, Florida. Technically, we were not required to do anything about the complaints because the directional array had not changed.
Nonetheless, I made sure that we addressed every complaint. In a couple of cases, I even built high pass filters for their TV sets. We replaced a few telephones too.
This is a far different case. The new tower is not the same height as the main tower.
I believe that CBS will be required to address the interference complaints ... but only when the tower is actually in use ... for a period of one year (unless the FCC rules have changed).
While much of the consumer equipment is exempt from the FCC's blanketing interference rules, it's good advice to keep your neighbors as happy as possible.
It's a sticky situation. I wish them luck.