Mortal Reminder should not costs 600G to build

Mortal Reminder = 600G Gains:

• 10AD
• Passive Duration lasts 5secs instead of 3secs.
• Gains 15% more bonus armpen

Lord Dominiks Regard = 400G Gains:

• 15AD
• Passive is now 1.5% (per 50HP) max of 15% instead of 1% (per 50HP) max of 10%.
• Gains 15% more bonus armpen

Lord Dominik's is given much more for cheaper, unless you want to try and justify that adding 2 more seconds to the passive is going to cost that much more.

To add: Executioner's Calling passive costs 275G according to Riot. http://leagueoflegends.wikia.com/wiki/Executioner%27s_Calling Since the 15 AD on the item is 525G and the item costs 800G.

So.. Why does it cost more? The item should be cheaper, or be given more.

EDIT: What I mean is that the cost in the recipe is more for Mortal Reminder.