这句话怎么理解？

问题如下：

Inside the offices of Panorama Investment Partners, Aisha Ishmael and Liam Lenihan, principals at the firm, are meeting to discuss some investment decisions for their flagship equity fund. The two companies they are discussing are networking equipment makers, Zip Technologies Ltd. (ZipTech) and Euronet GmBH (Euronet), both of which recently reported results for the fiscal year ending 31 December 2017.

Ishmael asks Burgess, “What have you come across with respect to the companies’ post-retirement benefits?”

Burgess replies, “I noticed that both companies are reporting net pension liabilities. Both companies amended their defined benefit pension plans during the year that just ended, providing enhanced benefits on past service to retain key technical employees. But I don’t understand why Euronet’s pension expenses were proportionately much higher year over year than were those of ZipTech, because both companies have similar workforces and the pension benefits were on par both before the amendments and after.”

Lenihan responds, “I think it’s because ZipTech reports under US GAAP while Euronet reports under IFRS and because of how those reporting frameworks account for past service costs.”

Lenihan’s response about the difference in ZipTech’s and Euronet’s pension costs is most likely:

选项：

correct because Euronet would have reported past service costs in net income immediately.

incorrect because ZipTech’s past service costs are reported in OCI and are not subsequently amortized to net income.

incorrect because both companies would have accounted for pension costs in the same way.

解释：

Lenihan is correct. Under IFRS (Euronet), past service costs are reported in net income in the year of the decision. Under US GAAP (ZipTech), they are reported in OCI and amortized to net income over the service life of the employees. As a result, in the year of the decision to award past service costs, the past service costs reported in net income under US GAAP are a fraction of those reported under IFRS.