It seems you cannot look at a behavioural accounting paper these days without a mediation or moderation model in it. Last summer I noted this was a concern of the Libby panel at the AAA Annual meeting http://aaahq.org/Meetings/2018/Annual-Meeting/Video-Gallery/Panel-Sessions. Session 6.01 on testing process theories.
And if you see such a model being tested 8 or 9 times out of ten it will be based on the Preacher and Haynes PROCESS macro that is available for SPSS and SAS. After reading enough reviews of papers using this approach, the best I can tell is that this is a poor sample size SEM at work! Indeed I recently came across a paper by Haynes and a co-authors (Montoya and Rockwood in the Australasian Marketing Journal 2017) that basically said that! see https://www.sciencedirect.com/science/article/abs/pii/S1441358217300265
Indeed as I read it I am not certain that the use of the bootstrapping option in most SEM packages would not do the same thing! So go ahead and use PROCESS macro when you are using a process model with only observed variables! but do not make claims about it that are not warranted! There is no superiority over SEM applications that I can see despite the mistaken claims of some – some that do NOT include Preacher or Haynes!