Automatic notification from subtask in "History" instead of "Comments" section

A client might have the "% done" on parent task calculated from "% done" on subtasks. When the subtask´s "% done" is changed, in the parent task in "Comments" section is automatically written "Automatically updated from subtask". When he makes a lot of changes on subtasks, the "Comments" section contains a lot of unuseful comments and it looks like that.

This modification would not save the Notice "Automatic Change from SubTask #ID" as a Comment to the Parent task but as a notice to Task History, so the Comments section will become more clear.