By Caroline Valetkevitch NEW YORK (Reuters) – The S&P 500 ended a choppy session slightly lower on Wednesday after minutes from the last Federal Reserve meeting showed policymakers agreed they needed to maintain a more restrictive policy stance. The minutes of the September meeting showed many Fed officials stressed the cost of not doing enough to bring down inflation. At the September meeting, Fed officials raised interest rates by three-quarters of a percentage point for the third straight time in an effort to drive inflation down from 40-year highs. Recently, Fed officials in their speeches…