I prepared a tax return for an Amish client. He is not subject to SE tax due to Form 4029. I used Worksheet A when calculating his EIC (he is married with one child)

Can't say which is accurate without all details, but if you did not include 1099 income not subject to SE tax that is incorrect. From pub 517 "

Earned income. 

Earned income includes your:

I found you this info:

IRM Procedures
• 21.6.3.4.2.7.3 (01‐25‐2016) ‐EITC SSN Requirements
• EITC is not allowed for "Amish" ,"Mennonite" ," Exempt Form 4029", or"conscience‐based objection" without a valid SSN, although the dependent exemptions and other credits may be allowed
• 21.6.3.4.2.7.4 (10‐01‐2016) ‐EITC Earned Income
• Form 4029 is approved –
• All wages, salaries, tips, and other employee compensation are earned income, even if FICA tax is not withheld
• Amounts received from self‐employment are not earned income
• Losses from Schedule C, C‐EZ, or F cannot be subtracted from wages

From: https://www.calt.iastate.edu/system/files/premium_video_files/Handling%20Tax%20Returns%20for%20Religious%20Groups%20%E2%80%93%20Amish%20and%20Mennonite3%20per%20page.pdf

2017

http://www.calt.iastate.edu

And this from an ATX forum: "per IRC 32 and 1402, earned income for EIC and Add CTC does not allow income that is exempted from social security (ex. housing allowance) to be included in the definition of earned income for credit computation purposes" and "I am in the middle of Ohio's amish country and I do lots and lots of returns for 4029 Exempt clients. SE income that is exempt from SE tax is NOT qualifying income for EIC and Additional CTC."

And there is a similar reference here:

"Employee Minister Income

Even if you have an approved form to exempt your income from Social Security taxes, if you get income for working as a minister who is an employee, count it as earned income. This income includes:

• Wages
• Salaries
• Tips
• Other taxable employee compensation

To calculate your earned income, don’t subtract losses on Schedule C, C-EZ or F from wages on line 7 of Form 1040.

Non-Employee Minister Income

If you get income for working as a minister who is not an employee, don’t count it as earned income.  This income includes:

• Self-employed wages
• Fees for performing marriages
• Honoraria for delivering speeches

For more information about ministers and earned income, see Publication 596, Earned Income Credit."

Hope that helps.