Amazon says customers receive orders 16 days earlier than expected, handling and shipping time is already less than that…

I have some products i sell with print on demand, these on average get finished and ship out within a day or two but can easily take longer so i set handling to 5 days. Packages on average take at least 2-3 days after processing to be delivered but can take a up to a week. Shipping profile is set for I believe 5 to 8 business day. Together my total time is about 13 business days. At the minimum it takes at least 4 days if everything is fast as possible leaving 9 days early out of the total 13, yet amazon tells me deliveries are happening 16 days early, which would be a few days before a purchase is even made if going 16 days back from my total processing and shipping times.

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Is amazon padding seller fulfilled listings with extra weeks of shipping and processing times causing it to “appear” to deliver early when it’s only because amazon randomly adds their own extended estimates? Is this just something that is normally off or inaccurate?

And if amazon pads things like this, does that mean i’m just hurting myself by padding them to be safe in the first place?