Can nursing homes give some residents 6 days /wk of rehab therapy to some residents, and 5 days / wk , based upon their insurance coverage?

A skilled nursing facility in NYS has the policy of giving short term rehab residents 5 days of therapy per week if their private insurance company will not increase the daily rate if they are given a sixth day of therapy. Some insurances will increase the rate, while others will not. If the rate is the same for 5 or 6 days of therapy, the nursing home gives the resident the option to pay privately for the 6th day of therapy. For residents with a private insurance company that only require 5 days for their daily rate requirement, are they entitled to the sixth day if they have a clinical need, without being asked to pay privately for it, provided that the rehab department is operational 6 days per week for other residents? If a resident has Medicaid coverage, I believe that they are entitled to the 6th day if there is a clinical need. Is that correct? Also, is there a regulatory reference that can be cited in either case?

Thank you