Qty based on meta data
This option allows you to split variations with different attributes in the bundle.
For example, you added a custom field to the product page (stored in the product metadata) to collect the value from the customer. The customer can choose the same option, but with a different value in the custom field. But you want the discount to only apply to a unique combination of variation and a custom attribute, and not be based on the cumulative amount of variation (which makes Qty based on variation).