You do have an option approved by DICOR. If you go to the DICOR website,
http://dicorproducts.com/catalog/roo...membrane/#care
That website link directs you to the "BriteTEK" (TPO) roof membrane. On that site, DICOR states, " apply Dicor lap sealant (#501LS, #502LS, #551LS) directly over the existing seal – allowing the new sealant to touch the EPDM and/or accessory surface."
DICOR 501LS is a "single tube sealant" approved for use on EPDM and TPO roofing membranes.
You can find DICOR 501LS at most RV parts departments...
There's no "specific requirement" to use the "2 part TPO specific sealant system" according to the DICOR website.