Clarify Amount calculation

[forsthug]

Clarify Amount calculation

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• [x] You've included unit or integration tests for your change, where applicable.
• [x] You've included inline docs for your change, where applicable.
• [x] There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

{Summary of the changes}

Description

{Detail}

Fixes #{issue number}

[volllly]

/azp run

[TSchmiedlechner]

/azp run