This is the HuCard pinout that I used. I could never find clear confirmation if this was the Turbografx or PC-Engine. I believe, based on the results, that it must be a USA pinout.
So does that mean the bits need to be flipped for both USA and JPN games on a PC-Engine? It appears so.
Confirmed, your pinout is the US-style pinout. You can see both pinouts here:
http://wiki.pcengine.info/pmwiki.php?n=HuCard.HuCardPinoutUS/JP games
do not matter; The ROM data should, ideally, be unscrambled, even for US ROMs (makes hacking, HES ripping, etc easier). With unscrambled ROMs on a US Turbografx, users will not have to do any bit-swapping, right, since the Flash chip->pinout is what the US Turbo expects.
The PC-Engine expects the reverse bit order, so us PCE users will have to swap the bits every time.
This is probably what sets apart your flash card from all previous ones: Tototek, etc cards were developed to run on PCE hardware primarily. Yours is expecting Turbo hardware. It's up to you to say whether that's a good thing or bad. ;-)