Cutlass is already expansive enough and you are rising the cost
Cutlass
25 AD and 10% lifesteal cost around 1250 gold and you are rising the price from 1500 gold to 1600 gold
Tiamat costs 1350 gold and has 10 sec cooldown. Cutlass has 90 seconds cooldown on active and costs way more. I don't think Cutlass's price is justified