For what it’s worth I’ve received two packages in the month of July and didn’t have to pay duty for either of them: both were over NT$2,000 but under NT$3,000. One Amazon, one iHerb. Either they aren’t charging duty on goods over NT$2,000 yet, or they’re not doing it very competently.
Both shipments had the US dollar value somewhere on the packaging, so the information is available for customs, although for the iHerb shipment they would have needed to dig into an attached plastic envelope. I didn’t see any indication of “You have ordered TWO packages and have FOUR remaining for the current six month period”, but who knows how or if the public will be informed about that.
iHerb (all groceries) came through with no hassles at all. For Amazon (electronics product), I received an email from customs (or whatever the associated office is), and needed to give them my Chinese name and my APRC number. After that it was fine. Fortunately no phone calls were involved.
Little shipping details: iHerb’s product shipping is quite good at letting you know where the package is, although don’t be alarmed by a “Shipment delayed” that seems to happen every time it arrives in Taiwan, I think just because the work day is over and everyone’s gone home until tomorrow. Amazon’s shipping info is weird and quite delayed; I got an alert that the package had arrived about 24 hours after I’d received it.