You need to add Employer Contributions to exclude its effect on periodic cost, thereby increasing PPC (because this is a cost to the employer, regardless of change in funded status).
CFAI subtracts a negative number (i.e. reflecting the contibution as a negative), so in effect it is adding it (just like Elan, which reflects the contibution as a positive number for the purposes of PPC). You end up in the same place regardless of forumla.
The text is a bit confusing, but understanding the concept above is the important part, then you can apply the formula and numbers as appropriate.
I think Elan did a better job explaining the reading than CFAI.
Elan consistently treats net pension obligation as a liability and PPC as a positive figure while CFAI poorly switches back and forth between treating PPC as a positive and a negative figure.
Essentially, the 2 formulas are the same
In Elan’s formula, it treats PPC as a positive figure, so employer contribution needs to be ADDED back to the change in the funded status to reflect the higher costs if the employer did not make any contribution.
However, in CFAI’s formula, it treats the PPC as a negative figure so employer contribution needs to be DEDUCTED from the change in the funded status to reflect the bigger costs. With that being said, In one of it’s EOC questions, it switches back and treats pension costs as a positive figure, which is just confusing and annoying.