Maybe take a read of this thread, which contains a well-written explanation of how to set up filter offsets:
I don’t use the filter offsets option so the following advice may not be correct, but I think having “0” as a focuser position is incorrect when using the offsets feature (as suggested by jmacon). I believe SGP needs a focus position entry for each filter, so try measuring and then entering focuser positions for Empty and Spect too.