Over here:

https://github.com/oitsjustjose/TiCon-Addons/blob/master/src/main/java/com/oitsjustjose/tinkers_addons/modifiers/ModAutoRepair.java#L94

you check world.getWorldTime(), which is the absolute time since the world started (so it also effectively encodes the moon phase and what often gets used as a basis for 'date' in some mods). It needs to be % 24000 in order to get the time value within a given day.

While I'm here, is it actually intended that your auto-repair works fastest in the nether?

Thanks, fixed :D

Also yes, it is intended; that's how it worked in TiCon 1. I don't know why, but I wanted to keep relatively original.

¯_(ツ)_/¯

Fair enough. :D