Abimelech lived at Arumah: and Zebul drove out Gaal and his brothers, that they should not dwell in Shechem.
Scriptural narratives are not always presented in chronological sequence, and it is not clear whether this destruction of the Tower of Shechem, the House of Millo, and the House of Baal-berith (three names for the same stronghold) took place before or after Abimelech sowed the city with salt, but it appears to this writer that the sowing of Shechem with salt would have occurred AFTER the events mentioned in this paragraph.