Negative-Cost Custom Field Items
We’re setting up our ski club trip signups and invoicing in WA for the first time. Some options we need to create have negative costs, like a lift-ticket discount for a senior or a “ground package” discount for someone providing their own transportation to the resort. WA will allow us to manually enter a negative-cost amount on an invoice, but will apparently NOT let us create a custom field that has a negative cost. It would be a tremendously helpful enhancement if we could create a negative-cost item (under Custom Fields). Please consider adding this capability – or perhaps it exists but it’s not apparent how to do it? Thanks!

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Nick Howe commented
Since invoices can now have line items with negative values, how about modifying the logic on the custom event fields to allow negative values in the 'extra cost' fields?