tenses - Struggling with simple past/present perfect in "Author X (2016) showed/has shown"

In my research article, I have many phrases that go like

1. 
   

   "Author X (2016) showed/has shown that"

   
   




2. 
   

   "Author X showed/has shown 2016 that"

   
   




3. 
   

   "The authors (X & Y, 2016) stated/have stated in their article that"

   
   
   

   
   
   
   
   

   • present perfect if the action was done in the past, but it does not matter when and already ended in the past or has no consequences to the present time

   
   

   • simple past if the action was done in the past at a certain time (yesterday, last year, 2016) and has already ended.

   
   

Following this logic, I would prefer present perfect in 1) and 3) but simple past in 2). However, reviewers suggested "showed" instead of "have shown".
What is your opinion of that, what would you prefer? I am writing using APA style by the way.