if they want players to spend more then don't raise the reward for the same price but drop the price itself.
i.e.
normal price: 6500 crowns cost 49.99euro
BHG offers new price: 11375 crowns cost 49.99euro (same cost + more crowns)
my proposal: 6500 crowns for 30 euro
reasoning: it is the cost that prohibits people from buying, not the actual amount of crowns. So by lowering the cost, you make the offer more tempting.