Calculation of Current Account Balance (International Macroeconomics)

Hi,

I was wondering if someone can help me with the following:

In some papers the current account balance is defined as the difference of net foreign assets in (t+1) and net foreign assets in (t). While some define it as the difference in net foreign assets in (t+1) and net foreign assets plus its interests in (t).

Can please someone explain me, why some authors take the income on net foreign assets into account for the calculations of current account balance and some don't?

Thank you very much.

Best,
Florian