Hi @Jessie_Barber ,
Thank you for reaching out!
Apologies for the confusion! Negative line items are only supported on one-off invoices, which is why you’re seeing that error.
For subscriptions or product line items, the best workaround is to manually set the price to reflect the discounted amount. For example, if your service is $500/month with a 10% discount, simply set the price to $450.
That said, I can definitely see how this would be useful for subscriptions as well! I’ll be sure to pass this along to our product team as a feature request.
If you have any other questions, please let me know. We’re always here to help! 