Your new inputs are as so:

Solution 6

NWC = [Cashflow(-50000,0,.05),Cashflow(50000,5,.05)]
print(NPV(NWC))
print(NPV(NCS)+NPV2(OCF,.2)+NPV(taxShield(100000,0,5,.2,.05))+NPV(NWC))

Notice net capital spending now has an inflow at period 5 of $50,000 and the tax shield now has 50,000 as the salvage value input instead of 0.

You should be getting a value of $92,872.73, your value goes up because now you can make $50,000 at the end of the period. Notice, though, that your tax shield will be less because depreciation charges are half of what they were before.