The accounting rules for valuing OPEB liabilities may be revised soon to take into account other promises that the employer has made to employees or in certain situations a course of prior conduct. For some companies, this may mean their overall liability is increased, while in other situations it may provide a decrease in liability.  It appears this change is being contemplated to arrive at a "truer" picture of OPEB liability.   See the article in the attached link for more information. 

NAIC panel wrestles with retiree benefits accounting