In V3.2.1 SPLINK command, X and Y coordinates of slave sprites are relative value to master sprite, but somehow Z coordinate is absolute value.
If V3.3.0 becomes available in US, not only X and Y but also Z will be relative value.
I figured out the relative position thing, which was what I expected, but it seems that the SPSCALE command affects that. But now I have a new problem, which I will post separately.
What you say is correct. SPSCALE on master sprite influences relative coordinates of slave sprites. If you expand master sprite twice as large as original size, relative coordinates of slave sprites will be expanded twice too. However SPSCALE on slave sprites DON'T influence relative coordinates.