2 scan bran is 1 syn so if you have a ryvita then that will be 1.5 syns so you'll be over. The ryvita wholegrain crackerbreads are 1 syn so that would make it right I guess.
The scan bran is on there to make the puffed wheat HEX have enough fibre to qualify, on it's own it isn't high enough so isn't a HEX.
Same for porridge for example, you need a scan bran to up the fibre to make it HEX.
Do you go to group? You get 10 scan bran in a pack for a pound.
It is up to you though, a lot of people don't bother with the extra scan/ryvita quoted in the book but it's worth having, even as a mid morning snack!