Pulled out the RSPduo and tested it. Same result as the RSP2pro, 8Mhz OK, 10Mhz nothing. Log files attached.
I have API 3.07 installed on system.
System is a Dell XPS8700, i7-4770 CPU, 16GB memory, NVIDIA GeForce GT635
USB connection is to PCI 3.0 adapter, w/connection to power supply, dedicated to SDR