[uncommon]

These CHA value does nothing, it's just a sort of spacer i think. If you look, all these adds 0 CHA.

About stacking, i think i figured how it works but i'm not at home. Will explain once i got back home.

Edit : Had my notes on my usb key so here is what i figured about.

Look at Ancient Aego for exemple :
1: Stacking: Block new spell if slot 3 is effect 'Max Hitpoints' and < 1300
2: Increase Max Hitpoints by 1300
3: Increase HP when cast by 1300
4: Increase AC by 69
5: Stacking: Overwrite existing spell if slot 3 is effect 'Max Hitpoints' and < 1300

Slot 1 type is 148 (Stacking1), min value is 69 value2 1300 formula 203.
The 69 refer to the "Total HP" type. From here it's pretty self explaining : it will block any spell that has a slot 3 type 69 effect that adds less than 1300 hps.
Slot 5 type is 149 (Stacking2). Basically the same thing except it will overwrite anything that has a slot slot 3 type 69 effect that adds less than 1300 hps.

The formula define what slot the spell should look at. 201 for exemple will check what's in the slot 1.

Take Focus of the seventh for another exemple :
1: Increase Max Hitpoints by 544
2: Increase HP when cast by 544
4: Increase STR by 75
5: Increase DEX by 70
6: Stacking: Overwrite existing spell if slot 1 is effect 'STR' and < 75
7: Stacking: Overwrite existing spell if slot 1 is effect 'DEX' and < 70
8: Stacking: Block new spell if slot 1 is effect 'STR' and < 1075
9: Stacking: Block new spell if slot 1 is effect 'DEX' and < 1070

Slot 6 is type 149 min value is 4 (which is STR) value2 is 75 and the formula is 201. It looks what's in the slot 1 and will overwrite any spells that adds less than 75str.