Thank you, @winged.
But why is SLS SRB so expensive? Also, one more thing about RP-0 costs that has bothered me, is that Apollo Command Module is ~6500 in Kerbal funds. Meanwhile, Orion CM costs 60000. I heard that Lockheed Martin, which is Orion's prime contractor, is sometimes called 'money blackhole'. But does it really have to be reflected in RP-0?