Blackeye5

So I had a stutter in my 06 R 500 when the transmission shifted into 3rd gear but only at low acceleration, it shifted fine when accelerateing more aggressively. I worked with a mechanic that I have known for 10 years and who always works in my vehicles. We identified that it was probably a solenoid and decided to replace all of them. When he spoke to the dealer to order the parts the dealer advised him to replace the whole valve body as the additional cost was only an additional $80. So he did that. We had the ECM Flashed at a dealer and everything seemed fine. Drove about 200 miles the same day. Just when I was getting close to home, I had either a couple of hard shifts or the rpm limiter kicked in. I was merging aggressively into traffic and gunned it pretty good. After the hard shifts the check engine light came on. I pulled over turned off the R and restarted. The check engine light was still on but the trans shifted normally. The next morning, I could not get the R out of limp mode. So now it is at the dealer and they are telling me that most likely the valve body is bad. Does anyone know what the warranty parameters are for a replacement of a brand new Mercedes part? The dealer is telling me that they will warranty the part but not pay for the labor. Does this sound right? They also will not let me take the car back to an independent to have the work done. If they want to replace the valve body there, shouldn't they pay for the labor also? Wouldn't this be part of a warranty claim for the part? Any ideas?