Health insurance premium expense seems treat differently among LLC, S Corp and C Corp. 

Please correct me if I am wrong.

If it is LLC entity on Sch C, health insurance premium is treated as tax deduction on Sch 1, line 17 Part two

If it is S corp entity, health insurance premium is included in W2 wage as taxable income but except FICA taxes. it also need to be included on sch1 line 17  Part two. (Does it mean health insurance premium under S corp not allow deduction)? 

If it is C corp entity, is health insurance premium included at line 24-employee benefit grograms on 1120C form ?