Here are the power levels when testing with the filter removed. The downstream power increased by about 3.5 dBmV from ~8.5 dBmV to -5.0 dBmV. The upstream power level did not change which is expected since the CMTS controls the upstream power setting and the filter didn't affect the lower channels < 36.8 Mhz. By the way, there is about 100 ft of cable from the multi-drop to the cable modem.
I don't fully understand the earlier comment that there was too much difference between the DS and US power levels. Do those comments still apply with the updated power levels?