Working time account calculation independent of target time

The working time account calculation must also work without the AZK function, which only uses the target working time. The AZK additions can already be calculated using a predefined weekly / monthly hours total (example: target working time 184 h, actual working time = 180 h; default: all hours over 173 h should be included in the AZK, i.e. 7 h = AZK build-up). However, this is not possible for the AZK deductions, as there is no option to calculate a difference between the work performed/booked and a specified weekly/monthly hours total in order to then post this as AZK deduction via rule 4.0 (example: target working time 184 h, actual working time = 168 h; default: only the difference of the hours between 168 h of work performed and the default of 173 h should be deducted from the AZK, i.e. 5 h = AZK deduction).