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Total machines can be setup to charge based on a summary of the meter counts from a number of child machines. This page works through one example of how this might be used
Using total machines allows you to group together related groups of machines for invoicing purposes. It also makes the structure of your machine database more transparent for management reporting purposes
It is possible to charge groups of meters from related machines together using meter groups, but total machines are now best practice in this kind of situation.
See: Aggregation and charging using total machines and subtotal meters
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