20% in certain types of self employed income (such as engineering consulting) is not taxable under current tax law.

Does this reduce self employed income for IRA limits by 20% ?

Example, age 66, only earned income is $7,500 in self employed engineering consulting. Is my traditional IRA contribution limit $6,000 or $7,000 ?
Are SEP IRA contributions calculated on $7,500 or $6,000 ?

Thanks !