Improved Destruction

[Coffey]

DDOwiki: Improved Destruction: Effect: On Hit: Your target gains a stack of Armor Destruction. (-1 penalty to Armor Class, -1% of its Fortification. 20 second duration. Stacks up to 15 times.) This effect may trigger once every second.

Notes: * (Improved) Destruction does stack with (Improved) Sunder

DDOwiki: Improved Sunder: Using this melee special attack, you may reduce the target's Armor Class by 5 and fortification by 10% on a failed saving throw for 24 seconds. Some creatures may be immune to the sunder effect. A successful Fortitude save negates this effect. Additionally, Improved Sunder will apply a -3 Fortitude Saving Throw penalty that lasts for 24 seconds on a successful hit (regardless of if they save). The saving throw penalty stacks up to five times (Maximum of -15 to Fortitude save). DC 14 + Str mod.

Does this mean that when the effect from Improved Sunder hits it will add to the AC debuff for an additional -5 up to -15 AC?

[Coffey]

My bad. It stacks to -20 AC and -25% fortification.