Discussion on B/S and I/S items relationship

From the chapter of post-employment , we can see some B/S table items are also existed in I/S table, like current service cost, past service cost,etc.

My understanding is if this B/S item can also cause revenue change, it will appear in I/S table too like the different costs.

If they can not cause revenue change, then they will not appear in I/S sheet.

Not sure if this is correct. Can someone help me make the relationship between these two tables more clear?

Thank you in advance.