[MovedGoalPosts]

Signal levels do change. It was probably needed when first installed to keep things within tolerances. If other customers are now online near you, an amplifier has changed (even due to temperatures in cabinets), all sorts really the signal strength may have altered).

I've often found that every few months an engineer has to come and tweak my STB's connection as the signal alters too much, each time they put a different attenuator on.