So I went through and checked spectrums work of their last coax job they did to my modem. .
So I re ran RG6Q obviously new connecters and for the hell of it replaced the ground block. . And here’s where I’m sitting at now.
Unless your "attenuator" is actually a multiple active amplifier device with bandpass filtering, the 10 dB attenuation applies in both directions, affecting both the US and DS levels. Your Spectrum techs or any junior college electronics instructor can explain to you exactly how that works.