[adbachman]

Could be. My experience (in multiple cases) was that they accepted bank deposit slips and Quickbooks invoice records, though.

It also has implications for unemployment insurance and SS calculations.

Your social security payout will be lower if you spent 20 years earning $50,000 than if you spent 20 years earning $100,000. Unemployment checks (which you can receive even if you're a self-owned s-corp) will be smaller too.

The long-term benefit assumes you weren't an idiot with the extra income. Even if it's post-tax, tucking the extra $$ away in your favorite safe investment vehicle will probably leave you better off over 20 years than whatever extra Social Security you would've made when you hit 65.