No. Potato starch and flour are not the same. Neither are corn flour and corn starch (and to make that one even more confusing, there's a place that calls corn starch corn flour, I think the UK, but they are 2 completely different items here in the US).
Tapioca flour and tapioca starch are, however, the same.
I would guess the same as Tanya that they likely just had different brands in front of them at the time.