I have both the ELM & the app, already checked out my codes and I did have an evap .
The obd doesn't do the emission test for you, and even if you erase the codes they will come up, and also if it's complete thats a fail too lol
I think they have something a bit different than that.
And I had an incomplete one too, went on the highway for 140kms yesterday and still nothing showed up. soo therefore gotta fix the issue in the system.