Why does Toughness cost so much more than Damage Resistance?
DR is a racial advantage (or a Supers advantage), while Toughness is an individual advantage that represents how much better at taking damage a character is compared to the rest of his/her species. An Unusual Background is included in its cost. For example, a sentient insect character with racial DR of 5 (15 points) could not buy more Damage Resistance, but could buy up to two levels of Toughness (another 25 points), making it an exceptional DR 7 bug. Source: Dr.