Yes the black non highlighted skills are confusing. I had a great CM that stayed in my team from 18 until he was 25 yo. At 25 years I noticed his strength was 1% despite being an 107% rated player. When I noticed this I trained him with a lot of strength and physical drills. He got 1% increase in the training but his strength still remained the same 1%. He had great shooting 200% and despite not having FK special ability he scored about 90% of his FK during his peak.