Thanks for your prompt reply, QDROphile.
I didn't mean to imply that the participant didn't follow the appropriate procedure for changing their deferrals. In this case, here's what happened:
1) The participant attended a live web-meeting where the employer representative indicated that the typical method of changing their deferrals was through the recordkeeper's website. However, the website limited the maximum deferral election to 60%. But, the employer representative indicated that if any employee wanted a higher deferral rate, they should call the employer representative and they could arrange a deferral rate as high as 90%.
2) Within days of the live web-meeting, the participant phoned the employer representative and requested a deferral rate of 90%. On the phone call, the employer representative asked the participant to email their request to the employer representative (presumably to create a written request?).
3) The same day as the phone call, the participant emailed their 90% deferral request to the employer representative, who emailed back a confirmation indicating that they had forwarded the request to the recordkeeper, and also said to expect a confirmation from the recordkeeper.