Does contributing to my SEP IRA affect my MAGI for ROTH IRA contribution limits if I am solely self-employed

I need this info for my 2019 taxes but I am referring to my 2018 taxes for now just so I have actual lines in the Tax forms to reference below.

From reading the IRA.GOV website and looking at Publication 590-A it seems:

•  If I contribute to a SEP IRA (Line 28 of Schedule 1 from Form 1040 for 2018) that does NOT affect the MAGI calculation for my contribution limit for a ROTH IRA.  Is that correct?
• The Deductible SE Tax (Line 27 of Schedule 1 from Form 1040 for 2018) also does NOT affect the MAGI calculation for my contribution limit for a ROTH IRA.  Is that correct?

I seem to be getting conflicting answers because:

• if I am understanding it correctly it seems as if the IRA.GOV website seems to imply you don't have to add back in SEP IRA contributions NOR Deductible SE Tax to your AGI (Line 7 of Form 1040 for 2018) when figuring your MAGI for ROTH Contribution Limits
• However some posts on this forum imply you do have to do so (at least for the deductible portion of the SE tax and maybe the SEP IRA contributions as well):     One such post is the following https://turbotax.intuit.com/tax-tips/irs-tax-return/what-is-the-difference-between-agi-and-magi-on-y... and part of it says:

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MAGI calculation

To calculate your modified adjusted gross income, take your AGI and add back certain deductions. Many of these deductions are rare, so it's possible your AGI and MAGI can be identical. According to the IRS, your MAGI is your AGI with the addition of the following deductions, if applicable:

• Student loan interest
• One-half of self-employment tax
• Qualified tuition expenses
• Tuition and fees deduction
• Passive loss or passive income
• IRA contributions, taxable social security payments
• The exclusion for income from U.S. savings bonds
• Foreign earned income exclusion
• Foreign housing exclusion or deduction
• The exclusion under 137 for adoption expenses
• Rental losses
• Any overall loss from a publicly traded partnership

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The above definitely includes needing to add back in One-half of self-employment tax and it mentions IRA contributions (but is unclear whether contributions to a SEP IRA are included in this).

Please advise because those two things make a HUGE difference whether my ROTH contribution limit for 2019 is $6000 or if I have to calculate an adjusted amount due to my MAGI being between $122,000 and $137,000.    

• Because if my MAGI means adding both my SEP contribution and my Deductible SE Tax back to my AGI, then my MAGI falls between those two numbers, but if I do NOT have to add those amounts back in then I am significantly under $122,000.

Because the IRS.GOV website definitely says the following:

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Modified AGI limit for Roth IRA contributions increased. For 2019, your Roth IRA contribution limit is reduced (phased out) in the following situations.

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Also, is there anywhere in TurboTax Home & Business for Windows for 2019 that will show me:

• my MAGI as it pertains to my max ROTH IRA contribution allowed?   -- OR --
• that shows me what my maximum IRA ROTH contribution can actually be?