I merged your latest post to this thread, as it's a continuance of this thread, and is best to keep details of the same issue together.
The capping station touching the bottom of the head was just one possibility/suggestion, but there are other things that could cause carts to empty faster than they should (including a combination of the following things: dirty or worn out printer parts, worn out cartridges no longer providing good ink flow, very low or high humidity and/or temperatures, or faulty carts- which is unlikely in your situation, since they've been working well for over a year). Since your carts are over 1.5 years old, and you have new cartridges- I recommend trying your new carts to see if they correct the issue you're experiencing with the old carts.
The fact that your nozzle checks and prints are coming out good is a good sign (more severe flow issues could give you trouble printing a good nozzle check, and/or ink dripping on the paper during printing). Keeping your printer clean/maintained is important to get the best print quality and longest life from your printer, so regular manual cleaning of the capping station and wiper blade are good for your printer health.
Please clarify- exactly what manual cleaning did you do (which parts did you clean, and what procedures did you follow)?
I hope this helps. Please let me know your results with the new carts, and let me know if you have further questions or there's anything else I can help you with.
Best regards~ Dana