I decided to have an Alpen Light bar today as my elevensies with a cup of tea. I don't usually eat them, but I had a couple in my desk drawer from when I'd bought them as a HEXB alternative.
I know that two bars make an HEXB because I see people writing it in their food diaries all the time - so I thought one would have been 3 syns. Not bad for a nice biscuit, I thought. Then I looked it up online and it was only 2.5 syns for a single bar. So SW obviously round things up to make the 6 syns that are roughly equivilent to a HEX. Not a massive difference, but it just reminded me that I need to keep checking values and not assuming!