I applied the following mod sets to 5's:
6.5% defense mod with defense primary
9.5% defense mod with defense primary and "+6" defense secondary
Defense mod with 1.15% defense secondary
Defense mod with 2% defense and "+4" defense secondaries
Potency mod with "+2" defense secondary
With the two mod set bonuses of 2.5%, my armor increased from 36.23% to 41.8%. And my resistance increased from 10.6% to 14.3%. That's a 15% increase for armor and a 35% increase to resistance. None of that makes any sense. How do the mod secondaries of "+2,4,6, etc" actually apply to armor/resistance?
Why not make it as easy as potency or tenacity mods?