First of all, if you do really borrow capital (which is a viable way of financing you working capital), the costs of it, that is interest paid, are already included in W_t1 (yet another entry in total costs).
Then W_t1 will be dependent on inflation or deflation, because the cost of the borrowing (the interest) will be higher in inflation (and W_t1 would be higher in inflation) and lower in deflation (and W_t1 would be lower in deflation).