Can discount codes and early bird discounts be used for the same order form?

We have always been under the understanding that if we have an early bird discount on a product then we cannot additionally use discount codes. Is this still correct?

If your ‘early bird discount’ is a promo code, then no. You can only use one promo code per form. You could, however, create a new promo code that would give the same discount as your ‘early bird + promo’