Are ABA/Costco/Amex incentives stackable?

Ask the Hackrs Buy/Finance
1

Looking for a lease deal in Maryland. Looks like most people have stacked Costco and ABA incentives. Is Amex stackable?

For example, for a 2024 Mercedes EQE 350 SUV:

ABA $6500
Costco $1000
AMEX $6500

2

Aba and amex are both the same fleet incentive

3

And either one is only net $500 or $1,000 more than the lease cash anyone else can get