Splits on a Standard Sheet and Modeled Sheet can be displayed on a Matrix report. Below is an example of a report with a GL Account with splits and two Modeled Sheet Accounts.
To add splits to the report, add the accounts to the rows. The accounts must be on the right-most column of rows within the report. In this report, a GL Account called Advertising was added to the rows along with two Modeled Sheet Accounts. One called Headcount and the other Salary. These are the calculations you would see in row details while in the Modeled Sheet. Select Report Properties and check the box to Show splits in accounts.
The accounts can be expanded by right-clicking on the account and selecting Manage Hierarchy. Expand the account. The three dots indicate there are splits.
Below is the Report with the splits: