I've never done a Zone 18 pick up for Free Now. I done 3 for Uber. All 3 were metered fares given to me as or before I dropped other Uber rides at DAP. I noticed that Uber only allows €1.50 of the €3.00 per job DAA fee commission free. As it happens two of the three I done were on the same Friday afternoon/evening and, on that day (for whatever reason), the entry and exit barriers to Zone 18 were open so I was wasn't charged the €3.00 so getting the two €1.50s added to the fare I entered (I didn't add the €3.00s that I didn't pay) contributes to the €10.00 that DAA charged me for an annual permit, I guess.
As an aside, I since realised that there is an Airport Drop Off fee (also €1.50) added to an Uber ride I took to DAP as a rider. The driver dropped me at the terminal so never paid any such fee to DAA. As we know, Uber determines what tolls/fees are added to fares so it was nothing to do with the driver. Maybe they have elected to split the pick up fee between drop offs and pick ups for some odd reason?