I am looking to buy GalCiv III with as many expansions as possible. Naturally I looked first to Gog. Sadly, there no discount for Black Friday but that;s a different issue. Now I noticed the mercenaries Dlc is priced 19.99 $ here compared to Steam where is half that (9.99 euro) . ALso, it seems that on Steam there is a gold edition/bundle which gets you the base game and all the DLC/expansions for 37 euros. So my questions are:

1. Is there anything similar to the Gold bundle on gog?
2. What's the reason for the different pricing policy?