This has to be a mistake. The book clearly states it costs 1 pp per point of hardness.Hardness +10: ... Cost: 0 pp; Total: 0 pp
If the sword has a damage bonus of +13 with energy damage +10 (enabled by Power Stunt: Extra Attack), then the powerpoint cost should be 13*1+10*(2-1)+2=25, for Weapon + Energy Field extra + one Power Stunt.Weapon (firesword) +10: Damocles carries a flaming sword with a damage bonus of +13L.
Anyone struck by it must make an additional Damage save against +10L damage for the sword’s fiery
sheath. [Extra: Energy Field; Power Stunt: Extra Attack (Energy Blast +10—fire); Source: Super-Science;
Cost: 2 pp; Total: 20 pp].
All other stats were okay. If one ignores these two errors, the total powerpoint adds up to that of PL 15.