Amplify Curse is bugged. Only increases base damage by 50%. It totally ignores the spell damage increase that the warlock has.
Google translate:
Amplify Curse Π·Π°Π±Π°Π³ΠΎΠ²Π°Π½. Π£Π²Π΅Π»ΠΈΡΠΈΠ²Π°Π΅Ρ ΡΠΎΠ»ΡΠΊΠΎ Π±Π°Π·ΠΎΠ²ΡΠΉ ΡΡΠΎΠ½ Π½Π° 50%. ΠΠ½ ΠΏΠΎΠ»Π½ΠΎΡΡΡΡ ΠΈΠ³Π½ΠΎΡΠΈΡΡΠ΅Ρ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΡΠΎΠ½Π° ΠΎΡ Π·Π°ΠΊΠ»ΠΈΠ½Π°Π½ΠΈΠΉ, ΠΊΠΎΡΠΎΡΠΎΠ΅ Π΅ΡΡΡ Ρ ΡΠ΅ΡΠ½ΠΎΠΊΠ½ΠΈΠΆΠ½ΠΈΠΊΠ°.