If you open the books you mentioned, you can see that Browse is under the category of "Common-use" programs, while Empathy is under the category of "Sensor Software" programs.
To further underline this distinction, Sensor Software and Common-use Programs are treated differently in the Programming table in unwired.
The "Adopting Software" pg. 136 in unwired specifically mention sensor-soft, and shaping complex forms basing them on the original program. Unlike normal complex forms that mimic programs without any referral and out of thin air, here you need to base the threading on something, which imply you cant improve it on the fly like normal complex forms.