Never got this to work with my 407etr (Canadian ezpass) transponder in my 2020 Merc GLE w/ heated windshield. Tried all the special areas (you can seem them with the right lighting) - never better than 1 or 2 out of 10 so I called the toll company.
They (407etr) have an exemption for vehicles w/ a "metalized windshield" - when applied to your account it essentially ignores the transponder and waives the camera fees. Hope this helps.