CRA indicates that the requirement for employer profit contributions to an EPSP cannot be waived
In approximate terms, one of the requirements to qualify as an EPSP is that the employer make payments computed by reference to profits to the plan trustee. CRA stated:
This means that there must be a binding obligation on the employer to make contributions pursuant to the plan’s contribution formula, and that such contributions must actually be made in the event of profits.
If this requirement ceases to be met because the employer no longer wishes to make contributions, the plan will cease to qualify as an EPSP – and it will be a question of fact as to whether it thereafter becomes a salary deferral arrangement, retirement compensation arrangement or an employee benefit plan.
Neal Armstrong. Summary of 11 February 2019 External T.I. 2018-0738561E5 under s. 144(1) - employees profit sharing plan - para. (a).