My friendly friend and neighbourly neighbor @baluch, did you try inserting their cable directly into your TV? The analog reception at my end is crystal clear. It is actually 200x better than showoff-time.
I don't think the reception should get worse in the evening, especially on the digital channels. Press the menu button on your digital remote, then go to the second icon on the left (installation), then select quick search. This section will show the signal strength and quality. You can edit the frequency to check other freqs as well. For instance 411, 379 and any other freq on which other channels are running. If quality is lower than 90 and signal intensity is lower than 77 or 76, you're in trouble. Check this in front of the cable guy (probably imran) and you should ask them to fix this because this will result in breaks and will also give you bad reception on analog. Ask them to make sure the signal strength is excellent.
Another thing to check is the video cable (they use a technical name for it which I don't remember, DV cable or something like that), the one that goes from the box into your TV's antenna slot, is of good quality. I bought a low quality one from a local shop which cost around Rs. 75 and the analog reception was very poor. I then switched to the cable I got from worldcall a few years ago which is of higher quality and the analog reception went to perfect.
Luckily, the problem on freq 435 appears to have been resolved. Not sure if my complaint to SDN did the trick but all of a sudden today, all 435 channels including Neo Cricket, Star World and Nat Geo Wild are now back to normal with zero breaks and 76-77% signal intesity.