net pension asset

I’m trying to summarize a few concepts here:

-If plan assets are greater than PBO, the plan is over funded & there is a net pension asset on the BS…does this imply this firm would book interest income under GAP in the form of net pension asset*discount rate…I do know that under GAP, interest expense is beginning PBO*DR versus under IFRS its the funded status*discount rate to interest expense on the pension plan…my question is how does it work under GAP and then under IFRS when the plan is over funded? Do either allow us to book interest income?