Treatment of Investment Income

Hello Tutor.
I Hope you are doing well.

My Question relates to
The Requirement of Preparation of Cash Flow From Investing Activities.
In Mim Co (Sept/Dec 21) and Moston Co (Sep/Dec 15).

As per Trial Balance, there is an Investment Income of $500 in case of Mims Co And $300 in case of Moston Co.

But in case of Mims Co they have not taken Investment Income under the Head of Cash flow Investing Activities.

Whereas in case of Moston the Investment Income of $300 is taken in Cash Flows from Investing Activities.

Can you explain me why they have treated a same thing differently in 2 different questions