I probably didn't do this right. What I did is put your code in a new plugin using postbit_display_complete as hook location. And nothing new appears (no Posts Per Day).
Wherever you want the value to show!, perhaps find where Posts: is already being displayed and add it under there, don't forget to add a phrase (or some text) for Posts per day and the html to have it on a new line..etc
In this other profile, still with kh99's correction, the errors are different. The nb for Posts Per Day is wrong (it displays again the nb of posts instead). The real PPD here is 0.24 (displayed just below).
Wherever you want the value to show!, perhaps find where Posts: is already being displayed and add it under there, don't forget to add a phrase (or some text) for Posts per day and the html to have it on a new line..etc
I don't know how to do this. I have absolutely no notion about coding and programming. All I can do is add code and/or remove code where someone tells me to. But thanks for trying to help.