Excess Roth Contribution with taxable earnings

I am under the gun from a time perspective and can't find an answer after doing some quick research. Client is in the Roth contribution phaseout. 2018 AGI is 192K. I know that if you have an excess Roth contribution the earnings on the excess are taxable in the year the contribution was made. So if the excess contributions were made in 2018 the earnings will be taxable in 2018. This will then change the AGI and change the excess contribution calculation. Can you exclude the earnings on the excess that are taxable in 2018 for purposes of calculating the excess so that it is not a circular calculation?

Thanks for any help you can provide!

Will the 1099 not come out in 2019 and taxable then? Taxable are earnings through the date of withdrawal.

The 1099-R will be in a 2019 1099-R but since contributions were made in 2018 it will be a code P - taxable in 2018.
Per pub 590
Withdrawal of excess contributions. For purposes of determining excess contributions, any contribution that is withdrawn on or before the due date (including extensions) for filing your tax return for the year is treated as an amount not contributed. This treatment only applies if any earnings on the contributions are also withdrawn. The earnings are considered earned and received in the year the excess contribution was made. If you timely filed your 2018 tax return without withdrawing a contribution that you made in 2018, you can still have the contribution returned to you within 6 months of the due date of your 2018 tax return, excluding extensions. If you do, file an amended return with “Filed pursuant to section 301.9100-2” written at the top. Report any related earnings on the amended return and include an explanation of the withdrawal. Make any other necessary changes on the amended return.

Anybody run into this? Do you include the earnings on the Roth pulled out in 2019 that is taxable in 2018 in the Roth contribution phase-out calc?