Your first post said 'test, sorry, please ignore' ... I eat posts like that for elevenses.
to the Forum. I never had an attenuator on my cable modem or STB, but have a look at the ones on yours and if you think you can get them off and on again without damaging anything, then I don't see why you shouldn't try, especially if the CSR suggested it. If you break something you can always blame them ...