Every official literature I've seen (in starter packs etc) says 5-15 syns a day (the mag confusingly says "around 10 syns" but then a non paying member can buy the mag anyway - you dont want to be giving all your secrets away!)
I really think that SW are trying their best to make it simple and straightforward for people - by giving a range to aim for - it means its not prescriptive, and so long as you are about right you will be okay.
But from reading this forum for a while now, it seems some people are really nervous about this freedom and want to know exactly how many syns they can have each day/week etc.
Its a guide. It means some days you might have 5, some days you might have 15, most days you will probably have somewhere in between, but in the end it all evens out so you are probably going to be fine. If you have more than 15 every day you might have a problem, or if you have less than 5 most days you could be heading for a fall (especially if you are feeling deprived), but just aim for the middle ground and you'll be fine.
Consultants saying different things in different groups really doesnt help either. Mine says you should still lose weight if you are having the full 15 syns every day - she says that even when people are struggling and I dont necessarily agree - I think that if you are stuck it might be worth cutting down for a few days - but then I'm not a SW expert so I couldnt really say.
I have seen somewhere on the official site about some people with more to lose being able to have more than 15 (randomly hidden in an article about flexi-synning for some reason) but aside from that its always been 5-15 per day.