i read this sentence as a negative way of saying: the full amount will be paid.
If the benefit paid from the CS Plan is reduced as permitted or required by law, the
amount of such reduction shall not be included in this offset".
*UPS/IBT will offset (cover) benefits accrued from the CS Plan at Normal Retirement Age
*if benefit from CS plan is reduced the amount of the reduction shall not be included in (part of) this offset
any real lawyers out there who would like to comment
I am obviously not a lawyer but there is a relatively current UPS headline (found on this site) which is a Motley Fool article titled "The Face of America's Pension Crisis" in which at some point in the article states that UPS is on the hook if the benefits are reduced.
The article also states UPS fought against a reduction in benefits for this very reason and that UPS lobbyists obtained some sort of carve out in a legislative bill in which UPSers would be the last to receive pension cuts if Central States had to start cutting back.
Based on the info in the article, I would say the conclusion in the the post I quoted is correct.