Elgin Grade 10, With a Curious Repair

Here's a grade 10 Elgin pocketwatch.  It's an 18 size, 11 jewel, movement, made about 1890.

It's hard to say what this is all about. The lower pivot hole for the 4th wheel (the seconds hand) has been milled away a bit, and also deformed some. Perhaps this was done to close a worn hole, but why grind it away like that?  It is neatly done at least.