So, you won't play because fishing or daily are not working for some days? I suggest you to leave now, because you will have way more hard times in classic
Create a spoiler, do some levels then go spoil https://l2wiki.com/classic/Hobgoblin until light blue and sell all coal for 3k (?)
Repeat
This is the easist way if you don't have an high lvl character and need money
Then if it works like that its bugged, because the damage must increase as the enemy's hp decrease https://l2wiki.com/classic/Fatal_Counter_-_Phantom_Ranger
Yes there is definitively a problem with ls, it should be like daggers skill (backstab, deadly blow) with fixed power, and not influenced by p/m atk that is a consequente bug. btw i already had reported this http://l2classic.club/forum/topic/11805-lightning-strike/