So far, I have only found marketing oriented documentation for the 550-010. No technical specs or manual.
I notice that the module has a power input jack, is the 9V power module connected and is the LED lit? I suspect the 550-010 contains a distribution amplifier, not just a splitter. If I'm correct, an un-powered distribution amplifier will not act as a passive splitter and you will not be able to 'push' signal through it with another amplifier.
Are all unused output ports capped with 75 ohm F-terminators?
Do you have access to a passive splitter, if so, how does it perform?
Rule of thumb: One amplifier
can be too many, two amplifiers
are too many.