To me, I'd say that it looks like no, you'd have to have not bought the base pack or either extra pack, so if you had held off and not got any of it yet, you save €10. If you have the Base Pack, or Extra 1 or Extra 2, you have to pay full price for anything more than that.

Depending on the eCommerce system, it can actually be quite hard to set up a discount system but I'll be honest here, this looks very much like shooting yourself in the foot in terms of customer relations to me, too.  :-?

Ian P.