Disabling the Plotname: entirely can of course not be done as this breaks the raw format completely.
The issue that might confuse some readers is the additional info written by Xyce in some cases:
Plotname: Step Analysis: Step 1 of 11 params: name = V1 value = 0 Transient Analysis
instead of the usual:
Plotname: Transient Analysis
George, as I said xschem already gets around this and reads correctly these files now, even if additional info is present in the Plotname: line.