Q: What do you mean by source code guarantee?
"What happens if I go over my plan?
If you go over your plan by 20%, we simply charge you for the next tier for that month only. We'll then revert you back to your the plan you last selected."
Very nice but the general idea would be to not do this so that people would tend to buy more than they need and then you make more money. From what you are doing you give don't give anyone a reason to purchase more than they have to by bumping to a higher plan. Not sure how much this matters given the tiers but I thought I'd throw it out there just the same because it would matter in other cases potentially. (Think back in the day of cell phone plans with minutes and how you were forced to buy extra minutes lest you get hit with a bigger charge.)
The main reason we're doing it is to put our customers at ease while we continue learning, not because we want it to remain a substantive part of our revenue at scale (because the linear opex is unattractive to us as businesspeople)