// borrowing seats from this level.
  // The server's concurrency limit (ServerCL) is divided among the
  // Limited priority levels in proportion to their NCS values:
  //
  // NominalCL(i)  = ceil( ServerCL * NCS(i) / sum_ncs )
  // sum_ncs = sum[limited priority level k] NCS(k)
  //
  // Bigger numbers mean a larger nominal concurrency limit,
  // at the expense of every other Limited priority level.