Sole Proprietor 401(k) Contributions

[MjInvestments]

I am a financial advisor who dabbles in 401(k) so I dont know a ton. 

I have a client who owns a business and has a Solo 401(K) custodied at Fidelity. So no real recordkeeper.

She put $18k in as an "employee contribution" in April.  She filed taxes yesterday and mistakenly tried to put in $27K as Employee and employer contribution ($9k employer contribution) and Fidelity rejected it because she didn't have enough cash in her account. She should have just requested $9k, but she forgot about her earlier $18k deposit.

Because she already filed taxes $9k this year is listed as Employer dollars.  Because Fidelity doesnt track Employee/Employer dollar differences in these type of accounts can I just basically say the half of the $18k deposit in April was employer dollars and request $9k be pulled today for another employee deposit? Would that cause any problems?

[ETA Consulting LLC]

You're saying that: 
1) She deposited her elective deferral in April?
and 
2) She waited until the extended tax filing deadline to fund her Employer Contribution and missed that deadline (due to a minor technicality)?
and
3) Because of the missed Employer Contribution Deadline in "2", you want to treat the deferral (deposited in April) as a $9K in deferral and $9K in Employer Contributions so that you can, then, deposit an additional $9K in Deferrals for the 2016 Calendar Year?

Please forgive me, I just want to ensure I have the details correct so that the members of the board can give you the information you require.

Good Luck!

[MjInvestments]

8 hours ago, ETA Consulting LLC said:

You're saying that: 
1) She deposited her elective deferral in April?
and 
2) She waited until the extended tax filing deadline to fund her Employer Contribution and missed that deadline (due to a minor technicality)?
and
3) Because of the missed Employer Contribution Deadline in "2", you want to treat the deferral (deposited in April) as a $9K in deferral and $9K in Employer Contributions so that you can, then, deposit an additional $9K in Deferrals for the 2016 Calendar Year?

Please forgive me, I just want to ensure I have the details correct so that the members of the board can give you the information you require.

Good Luck!

Yes thanks for clarifying better than I can - this is essentially what occured.

Important to note that Fidelity does not track the difference between employee and employer contributions, so basically they are just holding the assets. 

[Mike Preston]

There is still too much disclarity for my tastes.  What year was the April 2017 18k deferral supposedly for?  Was it 2016 or 2017?

[MjInvestments]

2017

[Mike Preston]

Then I don't see any problem with the suggested solution.