Factors in Determining 20% Service Level

[Flight33]

With respect to the 20%-level of bona fide services under the 409A definition of "separation from service," does anybody know what factors the IRS will look at to determine whether or not the (former?) employee is in fact performing less than 20% of his or her previous services?

In other words, how do they determine the level of services that were performed while working as well as the level of services performed after the purported separation from service? Time spent working? Projects worked on? Responsibilities?

What constitutes "bona fide services"?

Interested in hearing anybody's thoughts on this.