Keep in mind there are ACA employer mandate affordability considerations with opt-out credits. The approach you described might not quite fit an "eligible opt-out arrangement" without some additional tweaking.
Here's a short summary:
https://www.theabdteam.com/blog/how-the-aca-affordability-increase-to-9-83-affects-employers/
How Do Opt-Out Credits Affect the Affordability Determination?
The general rule is that the amount of the opt-out credit must be added to the employee-share of the cheapest plan option providing minimum value that is used to determine affordability.
Example: The employee-share of the premium for the employer’s cheapest plan option providing minimum value is $75/month for employee-only coverage. The plan offers a $25/month opt-out credit for employees who decline enrollment. Under the general rule, the plan costs $100/month ($75/month premium plus $25 opt-out credit) for purposes of the affordability rules to reflect the $25/month an employee forgoes when electing to enroll.
To avoid the need to add the opt-out credit amount to the cost of the plan, the opt-out credit must meet the definition of an “eligible opt-out arrangement,” which requires:
The opt-out credit is conditioned on the employee declining to enroll in the major medical plan; and
The opt-out credit is conditioned on the employee providing reasonable evidence (including an employee attestation) annually that the employee and all members of the employee’s expected tax family have or will have minimum essential coverage under a group health plan during the period of coverage to which the opt-out credit applies.
Note: In late 2016, the IRS indefinitely delayed these eligible opt-out arrangement rules for opt-out credits in place prior to December 16, 2015.
Action Item: If you are adding an opt-out credit, make sure that you follow these eligible opt-out arrangement conditions to ensure that the opt-out credit does not affect whether your offer of coverage meets an affordability safe harbor.