Thanks to all for the guidance. I found that I need to Reset before doing a new cal. The reference plane stays at the end of the cable, where it should. In fact, I now use a pair of 3-foot RG188 cables, and the reference plane is behaving itself. I use 100MHz and down, so the little things do not bother me. I wish the unit were heavier, as the RG188 cables easily drag the unit off the table!
