SYMPTOM:
Users can create custom subtotals in a report in Strategy Developer 9.4.1. If an attribute is placed on the page-by section of the report, the custom subtotal becomes an element of the attribute visible in the page-by dropdown, as shown below:

This will also appear as expected in Strategy Web 9.4.1 but it will not in Strategy Mobile 9.4.1, as shown below.
In Strategy Web 9.4.1:

In Strategy Mobile 9.4.1:

The custom subtotal is still seen at the bottom of the grid, however.
STEPS TO REPRODUCE:

CAUSE:
This is an identified defect in Strategy Mobile 9.4.1.
ACTION:
Strategy will continue to investigate and post updates as soon as they are available.