I was able to get over 13% off on a 2017 A4 in November 2017. I would think better discounts might be available now on a 2017 model. On the 2018 models, Audi is offering a promotion where the first month’s lease payment is covered by Audi. Have you looked at the 2018 models?
The A4 is a great car, and I believe is well worth the extra amounts you might have to pay over cars such as Volvos and Infinitis that are overpriced in the first place, and need huge incentives for dealers to unload them.