Apply tiered discount OR discount code

[jaycc]

We're using tiered discounts by spend amount but also use discount codes for various things. A customer can currently add a discount code after the tiered discount has already been applied which gives them a huge amount off. We'd like to prevent this from happening, but don't want to disable discount codes completely.

Ideal solution: Tiered discounts are applied but if a larger discount code is added it replaces the tiered discount. For example, the tier discount is 10% off but the customer manually adds a 20% off discount code. In this scenario the 10% off would be removed and the 20% off would be applied.

Second ideal solution: Tiered discounts are applied but if any discount code is added it replaces the tiered discount. For example, the tier discount is 10% off but the customer manually adds a 5% off discount code. Even though 5% is smaller the manually added discount code replaces the tiered discount and 5% off would be applied.

Are either of these solutions possible?

Thanks!