Sorry that's a typo above. Its 3 panthers, not 4.
Each line costs you 10cents = 1 credit, so thats 50cents if you play 5 lines.
You cannot change the amount of credits per line. Its fixed.
The button panel lights up to tell you how many lines you're currently playing during the spin, thats all. They are supposed to light up together with the line tags. Mine are all lit if I play 5 lines.
Oh OK. What I meant was that when I play 5 credits, only line tags 1 to 4 will light up. Line tag 5 is missing. If I play 4 credits. Line tag 5 is there, but grayed out as it should be. Will upload a screen shot tomorrow if I get a chance.