If you like the service you are getting, you are not doing the staff a favor by removing the auto-tipping. Here is how it works on Princess:
If you leave the tipping on, the auto-tip amount is pooled and anything you give over and above, the individual staff member will get to keep (after they report it). Say you left the auto-tipping on and tipped your room steward $20 extra on the last night. The amount in the auto-tip account is pooled. The Steward reports that you gave him $20 and once it is checked that auto-tipping is still in place, the extra $20 is returned to him, as well as whatever pooled amount he receives (say it's 80% of the $24.50 allocated for the steward or $19.60). In this example, the steward receives at total of $39.60 ($19.60 from the auto-tip and the $20 extra) of the $44.50 you gave.
If you remove the auto-tipping, EVERYTHING you give goes into the pool. Which means if you want to give an individual employee extra money for stellar service, he/she will not get the whole amount. In the example above, suppose you tipped the room steward the recommended $3.50 per day ($24.50 for a 7 day cruise) and an extra $20, for a total of $44.50. The steward must turn it all in and then he will only receive whatever percentage he gets from the pool. In this example, if the steward receives 80% of the pooled tips ($44.50), he gets $31.20. So, the steward gets $8.40 less than he would if you had left the auto-tip in place.
Either way, the money will be pooled. Thee is no way to avoid it. Employees do turn it in (if they don't they chance losing their jobs).
The only reason I would remove auto-tipping is toward the end of the cruise if you are not receiving good service. If service all around is good and you intend to tip extra, I would leave the auto-tipping in place.