im Warlord 70+.
I have 24lvl Heavy Armor Mastery and 28lvl Light Armor Mastery.
WL on 70lvl have 46lvl AM.
Thats im loosing ~10% of my p. Def.
Fix it
http://dnwiki.dragon-community.net/index.php/Mastery
Here, you have learned lv.24 heavy mastery and it's supposed to increases p.def by 75.5 on DN servers (slight more p.def than official server.)
If you really think you have lower status, post some required information to check your status (p.def on status, total p.def of your armor pieces, buffs if you had).