We compute the deferred tax expense or benefit in each period as the difference between the cash taxes payable to tax authorities and the tax expense computed for book accounting purposes in prior steps. This expense/benefit increases/reduces our net deferred tax liability ("DTL"), and we can now link our balance sheet to the net DTL schedule.
We chose to express deferred taxes as a net DTL, rather than as separate DTA and DTL, because of the complexity in tracking changes to the various components of each individually. Recall from Step 14 that we did track the change in DTA attributable to NOL individually, for illustrative purposes. Repeating that exercise for a dozen or so other items is too onerous, and we get to the exact same place by netting DTA against DTL. We could have as easily netted DTL against DTA, but since DTL often exceeds DTA, presenting deferred taxes as a net DTL frequently gives us a positive number that is more intuitive to work with.