My read was that they actually saved over $8000 per month:

- They mention that the initial savings of $1500/mo from omitting unnecessary headers was 12% of their egress cost (so the total before this was $12500)

- Then they got an additional 8% of savings by increasing the ALB idle connection timeout to 10 minutes (down to $10120)

- Finally they said they saved $200 per day by switching to a lighter TLS certificate chain ($6000/mo, so down to $4120)

None of those steps seem to have required any meaningful amount of development work. Let's say this took a developer one week? The return on that effort would be $100k a year, or $2500/hour for the first year alone.