Agree with Logixx. Current Miele's don't use a float. They use a flow meter that is contained inside of a part called the water path. You can see this part in the video above when they show water running through it. This part depending on the model can do many things. I have an older 7 year G2830. In mine this part has a water meter that measures the amount of water coming in. It takes a different initial amount of water based on cycle so it uses this to know how much has come in and how much finally comes in. In mine the Normal cycle takes the max amount of water that is allowed, other cycles take less amounts per fill. My machine is older, newer ones may act differently. This part also has the water softener resin at the bottom and the part has different paths the water can take.
This part is used to mix hard and soft water in some cycles, so in the beginning of the fill this part sends some water through the water softener and up into the tub from the bottom of the sump and based on the the water hardness, it will send some water around the softener and let it spill into the left side of the tub. When it is time to regenerate the water softener resin this part will send the water through the salt container, thru the resin and then down the drain, so there is a lot going on in this part.
I know this because some component in mine went bad after 3 years. My dishes were covered in white film right after the water softener regenerated. I called service, he connected PC to machine and it showed water softener fault. The repair guy came back the next week with the new part. I have the old one in my basement. I paid nothing for the part, nothing for 2 trip service call which could cost about $170 per at the time. This leads me to say the following:
I would at least get the 5 year service contract. In my case I had the unit installed by Miele and at the time they were offering 1 year contract, but 2 years if it was installed by Miele. So I had two years and at the end of that I got the additional 5 year contract. I have not had any other problems with the DW, but I did have problems with my T9820 gas dyer. I bought the extended contract with it also and in the second year it stopped heating. I called customer service and gave em hell. Because of the extended contract they came by the next week, took the old out and delivered the next new generation of that dryer and I paid nothing for it except the $250 I paid for the extended contract.
9 additional years for $510? Yeah I might do that too if it was offered. I am in no rush to buy new appliances any time soon regardless of how wonderful they are. With todays NA energy standards next time I buy something I guess it will clean without any water at all... and be a lousy clean at that.