Looks like same wwte coupons can work on several wwte-run sites (although not on the main one
Also, if applied on UK based sites (e.g. thomascook) the same coupon will save you 30 GBP, rather than 30 Euro (plus you may earn additional cashback or FF miles, depending on the site used). If anybody knows other sites that use WWTE software, please try applying coupons from other site and share your results.