[R-pkg-devel] package build warning

All,

I get the following warning using Roxygen2

* checking for missing documentation entries ... WARNING
Undocumented S4 classes:
  ?MortgageEffectiveMeasures?

The code to create and document the class is below

  #' An S4 class MortgageEffectiveMeasures
  #'
  #' A class of mortgage effective duration and convexity
  #' @slot EffDuration A numeric value the Effective Duration
  #' @slot EffConvexity A numeric value the Effective Convexity
  #' @exportClass MortgageEffectiveMeasures
  setClass("MortgageEffectiveMeasures",
           representation(
           EffDuration = "numeric",
           EffConvexity = "numeric"
         ))

The constructor function works and returns the class with the expected result.  The constructor function is documented as well as the generics and the methods.  So, I am a little puzzled as to why I am getting this warning.

I have tried removing all code and refactoring a code chunk at a time - no help
I remove the @exportClass and as expected I pass RCMD

I have looked at this and refactored it so many times if there is a mistake (and I missed it early on) I can no longer see it.  But it is a simple class and is fully documented in my package with the exception of the class.  Any suggestions as to where I should look next are be appreciated.