@TNT261
One of the first few chapters had him build "super" magic detector, because the best magic detector ball thingies only went up to 99. His "uber" magic ball created from the best barriers went to 999. And both showed him 02/002 magic.
Then at the end of the chapter the goddess talked about how his power level was 1002 and she just kinda forgot to tell him when she was explaining the barrier magic. Or something like that.
After trying to check his magic in his own magic ball he just accepted that his magic is "only" two and decided that it must have been him using barriers super efficiently that allowed him to pull off all this shit.