All Damage is an increase to all damage modifiers. 50% All Damage will increase the damage modifiers of fire, cold, lighting, physical and so on by 50%.
Total Damage is something that multiplies your full damage. It’s calculated right after everything else has been calculated.
Your calculations look correct:
“all damage” - additive bonus
“total damage modified” - multipltcative bonus
but the difference between “all damage” and “total damage modified” becomes more understandable if we consider more complex examples.
base:
10 + 10% physical
10 + 20% fire
bonus: + 10% all or 10% total
10 base physical damage gives 10 * (1 + 10%physical + 10%all) = 12 physical damage after bonus.
10 base fire damage gives 10 * (1 + 20%fire + 10%all) = 13 fire damage after bonus.
The final damage is then (12 + 13) * (1 + 10%total) = 27.5
Your 25 “all” damage was fine and then for some reason you did not multiply it by 1.1 to get the “total” damage.