I dont have as much data because i just started, but your flex numbers look very similar to my instacart experience.
I did a few deliveries to a Dell Web community. These folks have some money. And have been very nice, and tip well.
Here's an interesting thought. When an uber wants a ride with groceries they might not tip. But, they load and unload the trunk themselves. When i instacart, i feel i earned the tip. When i uber, i realize, i didn't really do anything extra.