Every time? Surely this is not common that he gets outaced. It happens against a few players who have both strong service plus return (Marat, Roger, etc.) but I don't think Agassi or Lleyton who are great in returns but not as much in service, ever did outace him.
Agassi is a bad example, he's been relatively easy to ace the last few years. Marcos had one more ace than him in Melbourne, MURRAY had one more ace than him in San Jose, Benneteau had 4 more in Memphis, Andreev had more in IW.
It's that his return his poor. It's not a serving problem.