Any further explanation would have to be made under your methodology section. Frequency and duration are important because they will help all parties to clearly understand what is expected of them. It will also help ISC s to better monitor the plan of care. Is not always the same as the date the plan begins, so make sure that this is accurate. Your assessment information, needs list and client rights modifications should all contribute to the answer to this question.
Previous achievement is the percentage of completion criteria achieved during the previous plan.
If it is a new objective then simply write that on this line. If you are running a baseline to establish basal performance, write baseline here. But just changing the completion criterion does not make it a new objective. The methodology serves as the instructions to staff, so whatever you want them to do must be written down. The steps to a task analysis, the tasks included in a routine, and the data collection methods all need to be included.