I was wondering something about fl and ranged combat formations. if you have 5 flamers back by 4 enhancers cound you have the first 3 of them flame for 5 damage? primary + 2 damage from support, +2 enhancers. the next 1 flame for 3?, then the last 1 for 2? thats 10 damage for 3 actions and whatever formation approched you is toast. I believe this is correct but it seems to powerful so I wanted to be sure we are not doing anything wrong.

f f f f f
e e e e

You can't use F/L in formation unless your only targetting one figure. In that case why bother with F/L, so the ranged attack would do normal damage of +1 damage per member of the formation and +1 damage per figure with ME.

where does it say you can't flame in formation? is that just in conquest or also in rebellion?

According to the Unlimited rules you may only use a formation attack when the intent is to harm a single figure.