I understand that the cash outflow at the beginning as well as the benchmark part.
However, I don’t understand that why the short call value has to be deducted from the NEW long equity position. Could anyone explain a bit on this part? I might have missed something here.
Many thanks in advance.
Same issue here… someone please respond! 
Your “portfolio” = What you are long - what you are short.
You OWN shares, you SOLD calls. Thus, as Call option price increases, your value goes down. Which (should) be offset by what you bought for your hedge. Remember Delta is not constant, it changes with both time and the change of the underlying.
Risk Management - Options - 4.1
Long +
Short -
Like in futures gain/loss calculation. This is value of position on time T1 if T0 was a purchase date. The only doubtful thing for me is why at FUT we consider only difference in FUT price between T1 and T0 and at delta hedge we consider full price in equation (#shares x option price and not #shares x difference in option price between T1 and T0). Same with underlying shares.
Not sure if it’s correct. I try to intrepet that my entire hedging plan includes the long and short position. if i wanna close the plan, i need to close both long and short and therefore, i need to count the value changes of short position and then compare with the benchmark.