> ## Documentation Index
> Fetch the complete documentation index at: https://docs.slm.m1amdocs.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Understanding License Based Quantities

When billing for license-based rated products, use the Quantity field for the related AutoBill Item to specify the number of licenses to prepay.You can change the quantity at any time during the billing cycle, using either the autobill.modiby() method or through the Subscribe portal. Proration of mid-cycle changes is available using the same proration parameters available for all modifications.

**Parent topic:**[Working with Rate Plans](../topics/ProgGuide_RatePlans)


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