The amounts that are withheld from employees are not a deduction for the employer.
The amounts that the employer has to pay in addition to the withheld amounts are deductible by the employer.
For example, on $1000 of wages the employee has to pay $76.50 for FICA and Medicare.
When the 941 is filed the employer has to match and pay another $76.50.
The total paid with the 941 in this case is $153.00 and the employer deduction is $76.50.
Please ask if you need clarification.