2005 Buick Rendezvous Power Steering Fluid Overfilled

1. Sever Power Steering Fluid Leak [Wife's car]
2. Mechanic replaced power steering pump and high pressure hose.
3. Two days later wife says steering sounds funny.
4. I checked fluid level and it was WAY overfilled.
5. I salvaged excess fluid and took to mechanic. Told him I wanted him to be aware in case excess fluid caused excess pressure and damage to any seals.
6. About 6 weeks later wife says again, steering seems "funny".
7. Check fluid level and it is way down so I take back to mechanic.
8. Mechanic says driver side power steering rack is leaking, $900 to fix via replace entire steering rack. Says not related to "overfill".
MY QUESTIONS:
DID EXCESS PRESURE FROM OVERFILL CAUSE PROBLEM? TO REPAIR, MUST I GET WHOLE NEW RACK OR CAN I JUST GET A NEW PIPE/TUBE IN THE STEERING RACK [MUCH LESS EXPENSIVE]?