I assume you are entering that 10 inches as the seismic anchor motion (ASM) for shocks 1 & 2 and zero for the ground shock.
In addition to the inertial component, the program will calculate the response to each individual ASM and then sum these individual ASM responses according to your Control Parameter settings - either absolute or SRSS.
Your node 40 will see a Shock1 ASM component and a Shock2 ASM component (with the anchor at 60, I believe there will be no response from the Ground Shock). But the ASM will be a combination of (10" at 10 with 0" at 60) and (10" at 60 with 0" at 10). To that, add the inertial component to get your total response.
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Dave Diehl