No subnumber summarization for retirement simulation

What causes this issue?

You are calling the retirement simulation with subnumber summarization
in report RAGITT_ALV01 (asset history sheet).
A runtime error has occurred.

How to fix this error?

A retirement simulation is only possible as an individual list (List
assets) or totals list (...or group totals only).
Individual list:
You start the asset history sheet with the retirement simulation as an
individual list and summarize the assets by main asset number in the
list viewer (ALV list).
Totals list:
You create a sort variant in which the main asset number (ANLAV-ANLN1)
is defined as the lowest sort level and call the asset history sheet
with the retirement simulation as a totals list.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.