You are not allowed to have any dates not covered by orders, so the 485 needs be dated just like always, with the From date 1 day after the To date of the previous 485.
The key is documenting why the visit was missed, how it was found, and whether or not this is a problem that requires policy/procedure interventions or staff training.
If there was a visit performed in the 5-day window, some agencies convert this visit to a recertification visit and move the recert documentation to that visit. This method does not apply if no visit was made in the 5-day window by a discipline allowed to complete an OASIS.
Although it is not explicitly spelled out in the CoP, the expectation that accompanies the requirement to update the comprehensive assessment between days 56 & 60 is that the orders for the ensuing 60 days will be based on the results of that assessment. The patient's care orders essentially expire at the end of day 60, so day 61 begins a new payment episode. The agency should be aware of potential legal issues associated with completing the assessment late, considering that the agency may not have orders for visits after the end of the 60-day period. If the patient is a Medicare patient, you should discuss any payment-related issues with Medicare Administrative Coordinator (MAC).
Helpful link with OASIS Q&A: http://www.oasisanswers.com/aboutoas_links.htm
Click on Link OASIS Q&A and then click on Category 3: Follow-up Assessments. Scroll to page five to view information related to this situation.
If you need to select an OASIS for billing that is dated outside of the 5-day window: Make sure the episode 485 dates has already been created and shows up under Billing > PPS Billing > Edit PPS Episode. Select the episode and then click on Select a Different OASIS. Click on the OASIS and run the RAP Claims screen to update the 1st Visit Date information.