Short answer no!
Revenue say ” The employer is expected to make best efforts to maintain the employee?s net income as close as possible to normal net income for the duration of the Subsidy period. There is no minimum amount that the employer must pay as an additional payment in order to be eligible for the scheme, but the employer will need to enter at least ?0.01 in Gross Pay when running its payroll. “
So if you are not topping up the scheme you must add a payment amount of ?0.01 on to have the PSR accepted