Like Extra|Statistics, Project Statistics will create a new tab with statistics. It will compute the same statistics, but for all files in the current project rather than the current file only. The order of the files in the statistics is the same order as in which they are arranged in EditPad Pro's tabs. If you want the files to be sorted alphabetically, use View|Sort Tabs Alphabetically prior to using Extra|Statistics for All Files.
View|Sort Tabs Alphabetically