(STOCK-STOCK)/OPTION=T T=1
(STOCK-STOCK)/OPTION=1 is step to recover the price of option by T to support the stock.
(S-S)/S=1 is step to recover original investment on the stock market.
(S-S)/O=T has T to keep 1 in order to explain. (S-S)/S=T to keep 1 in order to recover original stock than option.