If u have raised a complaint, then they cant get away without ur signature. So u do not accept any sort of explanations given by them over phone. U talk to them face to face, see how much efforts they are putting in, and after that if they are able to achieve atleast 95% on the Quality and strength, that should be fine. But that is, after they have really tried a lot.In our area the engineer always used to tell that quality has to be 100%. Strength can be a little lesser......i was told this when i first upgraded to HD DVR. I dont remember if i mentioned this in my review at that time......when the initial installation was done the signal bars were less than 100%. I used to face stuck screens/pixelation etc nagging issues. But then i lodged a complaint to little higher levels & they sent a senior person at my place. That person then made the engineers work in order to get the quality to 100% & strength, a bit less than 100. He clearly told me that for HD, Quality has to be 100%. If someone says it cant be achieved, then that person is lazy.