Item price settings

Hello

Someone know where need adjust an upgraded item prices?
example:
Aramid Martialhelm +0 2700 Alz
Aramid Martialhelm +1 4050 Alz
Aramid Martialhelm +2 5400 Alz
Aramid Martialhelm +3 6750 Alz
Aramid Martialhelm +4 8100 Alz

I see the pattern in that [Base Price] + [Base Price] * 0,5 * [Upgrade Level]