First stage dealer buys goods at 10 % excise duty and later

Dealer can raise Invoice with proportionate Excise duty passing (duty means purchased Invoice, this is the supporting document & duty rate purpose).

non related FSD/SSD can not change the rate of duty,

however if the FSD is the depot of the manufacturing factory, then depot is the point of sale, in this situation sale is effected at depot sale point and rates prevailing would be applied.