Servos offering souls to Specters

[Technomage]

For those who don't know, if you have both Discover University and Paranormal Stuff downloaded, a Servo is able to offer up parts of its "soul" to specters, despite not having ghosts.  How does that work?  Do Servos actually have souls, just not enough to manifest as ghosts?  Or are they offering a kind of "soul substitute" to specters (such as some battery energy or something)?