If you're wiping the entire drive and the firmware isn't buggy, you should be ok - but being sure that single file(s) are actually deleted is not likely.
They are not incompatible messages at all. This article says that SSDs delete stuff fast; the other says you can't reliably delete particular things. Basically, they're unpredictable. You can't reliably expect a particular file to be purged, and investigators can't expect data to stick around. So it might stick around, it might not, and no one has direct control.
If you're wiping the entire drive and the firmware isn't buggy, you should be ok - but being sure that single file(s) are actually deleted is not likely.