The metamagic system in Dungeons and Dragons Online has undergone significant changes in Module 5.0: Accursed Ascension.
The biggest change that casters will discover is that each metamagic feat other than Heighten Spell now has a fixed spell point cost increase rather than multiplying the spell point cost of a spell as they did before Module 5.0. These surcharges are as follows:
Empower Spell: +15 SP
Empower Healing Spell: +10 SP
Enlarge Spell: +10 SP
Eschew Materials: +2 SP
Extend Spell: +10 SP
Maximize Spell: +25 SP
Quicken Spell: +10 SP
Heighten Spell: Special (Changes base cost of your spell to that of your highest level spells)
These cost increases are cumulative if multiple metamagic feats are active simultaneously, so a Quickened, Maximized, Enlarged Fireball would cost:
20 (base) + 10 (Quicken) + 25 (Maximize) + 10 (Enlarge) = 65 Spell Points
Improved Metamagic enhancements have all been changed to flat cost reductions on these surcharges. Sorcerer Improved Maximizing III, for instance, has become "Using the Maximize Spell feat costs you 9 fewer spell points." Wizard Improved Heightening II is now "Using the Heighten Spell feat costs you 2 fewer spell points per level of heightening."