Guys how much does blue cross ppo insurance covers?

well i live in chicago and my dad has it he got it before we had hmo but he switched to ppo im not sure but i think blue cross ppo covers only 15% is this true because i heard my dad talking about that i just want to be sure because if it does cover 15% we are screwed but i was reading this other question similar to mine and the guy said it covered 80% so whats up