"and the self employment taxes are really high"

You're not Saving anything. All this does is Shift them around. Instead of the Schedule C business getting the expense deduction, the S Corp gets the expense deduction, and that still is the same person's pocket, really. This is not a reason to decide to become a corporation.

Have you looked at the math on the SE Form? That's where your client already gets their "employer" share of SE tax as Expense. That's why you see "92.35%" as:

"Generally, the amount subject to self-employment tax is 92.35% of your net earnings from self-employment."

Here: https://www.irs.gov/taxtopics/tc554

It's reiterative. The 1.45 + 6.2 for Employer is credited to the business, and that's why there is that reduction.