This is currently possible under reports and via the analytics side. For advanced ad hoc reporting we would provide access to centralised aggregated reports using the analytics connection. Functionality within Tableau for example allows you to create animations of data changes over time.

A selected item not yet purchased can simply be removed. If an item has been purchased the operator can view a transaction report for an individual (that has identified themselves) and go into refund mode to modify a transaction. That creates a refund translation and issues a refund to a user's account.

The system runs two purses/wallets, cash and subsidy. The rear facing screen however only shows cash amounts, so subsidised transactions would look almost identical therefore anonymising free school meal accounts