Frequency Offset is a field in the PM Task Editor. It can be used to change which PM Task a job step (Preventative Task) is in without altering the overall frequency.
Use of this field can assist in PM Optimisation processes by allowing effort or downtime to be levelled across different PM Task frequencies, reducing overall downtimes. Below is an example of how the Frequency Offset field can be used.
A simple maintenance strategy has four (4) preventative tasks to be performed:
| Preventative Task | Frequency | Frequency Offset | Unit of Measure |
| Task A | 2 | 0 | Weeks |
| Task B | 2 | 0 | Weeks |
| Task C | 4 | 0 | Weeks |
| Task D | 4 | 0 | Weeks |
Upon generating PM Task OnPlan would create two (2) PM Tasks as follows:
| PM Task | 2 Weeks Inspection | 4 Weeks Inspection |
| Job Steps Contained | Task A Task B | Task A Task B Task C Task D |
The 4 weekly inspection has more labour effort required as it has four (4) job steps compared to two (2).
The Frequency Offset field can be used to level the labour effort between the two (2) PM Tasks. If the maintenance strategy was instead:
| Preventative Task | Frequency | Frequency | Unit of Measure |
| Task A | 2 | 0 | Weeks |
| Task B | 2 | 0 | Weeks |
| Task C | 4 | 0 | Weeks |
| Task D | 4 | -2 | Weeks |
Upon generating PM Task OnPlan would create two (2) PM Tasks as follows:
| PM Task | 2 Weeks Inspection | 4 Weeks Inspection |
| Job Steps Contained | Task A Task B Task D | Task A Task B Task C |
The -2 Frequency Offset of Task D moved it from the 4 Weeks PM Task to the 2 Weeks PM Task, since 4 - 2 = 2. But since the Frequency of Task D is still 4 Weekly the task will not be added to the 4 Weeks PM Task.
Note: If there was another Preventative Task in the maintenance strategy with a Frequency of 6 Weeks, Task D would be included in the 6 Weeks PM task, since 2 + 4 = 6.