Subject: Re: Partial IRA to Roth Rollover
I thought that the IRS says pre-tax and post-tax amount must be taken ratably, i.e. proportionately. That is certainly how withdrawals are handled.

My Fidelity rep thinks so too, now.

Here's the IRS guidance from 2014:
https://www.irs.gov/retirement...

Many savers have made after-tax contributions to a 401(k) or other defined contribution retirement plan. If your account balance contains both pretax and after-tax amounts, any distribution will generally include a pro rata share of both.

I've read the rest of it a few times and am still not seeing what the Bogleheads are seeing - that I could rollover the pretax to the 401k and after tax to a Roth, without paying tax.

I have gone ahead and rolled all my SEP IRAs to the 401k. When I have the income space I can roll the comingled IRA to a Roth, paying tax on the pre-tax portion. That seems safest.