Good Question!
In case of B2B (Cable wires to institutions) they(KEI Industries, I think its a industry practice) purchase inventory against orders .
In case of B2C (Retail) they revise retail prices as per avg inventory cost every 15 days.
What this means that In case of copper price down trend obviously EBITDA level will recede however how much will depend upon how long the inventory cycle is in retail business.