Scheduled Payments for Non Spending Plan Accounts?

Is there any reason why Scheduled Payments only show for accounts that are in the Spending Plan?

I have accounts outside the Spending Plan which I have added Scheduled Payments to; but these Schedule Payments do not appear anywhere.

I understand that Schedule Payments are used to show future spend/credit against the spending plan, but I also need a way to be able to look at all scheduled payments for an account to allow a view of committed spend for that account. Currently I don’t seem to be able to do this.