Agree with Susan.  See Sec. 2301(e) of the CARES Act about the applicability of IRC Sec. 280C(a) and the explanation in the JCT report, which includes the following example:

If a taxpayer claims a credit under this provision, rules similar to the rules of sections 51(i)(1) and 280C(a) apply. Thus, for example, an employee retention credit may not be generated by an individual employer hiring his or her children. In addition, the credit is taken into account for purposes of determining any amount allowable as a payroll tax deduction or deduction for qualified wages (or any amount capitalizable to basis). For example, assume an employer pays $2,500 of qualified wages for the quarter and claims an employee retention credit of $1,250 for qualified wages paid during the quarter. The employer’s resulting OASDI tax liability (under section 3111(a)) for the quarter is $155. Under the provision, the employer reduces its payroll tax expense by $155 and may deduct only $1,405 of qualified wages (assuming such wages are not subject to capitalization).

Footnote: $2,500 – ($1,250 - $155) = $1,405.