The S7 every single unit had a customs fee
So I'm not surprised the trend is continuing, IMO the US customs is now wel aware who Bitmain is and what their products are, and as such they are unwavering on the customs fees
I did not had any fees in US on seven individual S7 units of which most expensive was $1823 or something like that.
I also never had a fee on S1,S2,S3,S5. I also did not get fees on expensive Spondoolies.
I conclude that it is not that they are unwavering, it is that customs rules are not very well defined.
I very well may get a fee on S9, but it would mean that something changed, not that it was there all along.