Reimbursement of Medicare premiums

We have a small business w 10 employees and the business offers health insurance.  So the QSEHRA is not available.  Two employees have chosen Medicare instead of the employer health plan.  The employer pays 75% of the health insurance premium and employee 25%.  The employer wishes to reimburse the Medicare-covered employees 75% of the Medicare premium they incur.  There appears to have been a pronouncement in 2015 which allows for this provided certain conditions have been met which they have in this case.  So it appears to be allowable.

Questions: Is this still an allowable benefit?  Does there need to be a written plan?  If so I suppose it would be an HRA.  Can the HRA only address and cover the Medicare reimbursement issue?  I assume the reimbursement would be non-taxable.  

Comments? Thanks

See Q&A-3 of Notice 2015-7. It seems that as long as the Medicare folks were offered the employer's health insurance plan and declined it, and the Medicare reimbursement is limited to Parts B and D, and Medigap, as described in Q&A-3, you should not have a penalized "employer payment plan" under what you describe. Otherwise you would. The Q&A also points out there may be issues under Medicare Secondary Payer. However, if you have fewer than 20 employees (check the way CMS counts this), you should be OK. Anyway, I think all that MSP would knock out would be the Medigap premiums, not the Parts B and D premiums.