So now that I'm thinking of it, I might be able to see how the tip thing matters for speed of delivery, which of course will change everything regarding what I tip (aside from the cases where I'm willing to wait 5 days for the delivery).

Earlier this morning, at the store where slots where open, I could chose from:

- "Today through April 18"
- Apri 18
- April 19
- April 20

So I asked myself, "What the fuck is 'Today through April 18'? Why can't they give me a narrower time frame than 5 days?"

Maybe that's how the tip works. If you get one of those slots (which I assume open up again late at night), the delivery people probably pick deliveries from "most lucrative" to "least lucrative". So the higher you tip, the closer your delivery will be to "Today" than "April 18".

Is this how it works? Anyone know?

If it is, then 20% will probably have to be my norm, sadly.