If forceExpectation = TRUE the distribution is transformed by dividing the random variable with its expectation and using the change of variable function.
References
Gomez-Deniz Perez-Rodriguez (201X)
Non-exponential mixtures, non-monotonic financial hazard functions and the autoregressive conditional duration model. Working paper. Retrieved June 16, 2015, from http://dea.uib.es/digitalAssets/254/254084_perez.pdf.