Upon partial retirement depreciation is recalculated based on remaining cost instead of NBV
Asset Cost added Jul-18 = 100,000
Monthly Dep (10%) = 8,333
Acc Dep as on 31-Aug-18 = 16,667
NBV = 983,333
Partial Retirement (Sep-18) = 500,000
NBV Remaining = 491,667
Dep calculated by system for Sep-18 = 4167 (8,333 * 500,000/1000,000)
Should be = 4097 (491,667 * 10% / 12)