Step 1 :Calculate the book value at the point of revision. This is the initial cost of the equipment minus the depreciation for the first year. The depreciation for the first year is calculated using the straight-line method, which is (Cost - Salvage value) / Useful life. In this case, the useful life was initially estimated to be 5 years. So, the book value at the point of revision is \(67800 - \frac{{67800 - 2000}}{5} = \boxed{54640}\).
Step 2 :Calculate the remaining depreciable cost. This is the book value at the point of revision minus the salvage value. So, the remaining depreciable cost is \(54640 - 2000 = \boxed{52640}\).
Step 3 :Calculate the depreciation per year for years 2 and 3. This is the remaining depreciable cost divided by the remaining useful life, which is now 2 years. So, the depreciation per year for years 2 and 3 is \(\frac{52640}{2} = \boxed{26320}\).
Step 4 :The revised depreciation for both the second and third years is \(\boxed{26320}\) each year.