Responsiveness was one of my goals, but part of that just comes from it being a compiled language rather than a spreadsheet.
Let my know if you still have trouble later.
Nah, it is more than just efficiency of executing compiled code vs. vb-script and macros in excel. I find usability of winPCD more manageable, like having moveable windows for the main program, the system graphs, and updateable schematic diagram. It makes making changes to the XO, seeing the results, and going back and forth...easier.
Regarding the original problem, I can confirm that changing the electrical order from second to first solved the issue. But it may have exposed another one [or made clear the underlying issue]:
When I save the change to the same session file (replacing it), then re-open, the change is not saved, i.e. the midrange high pass still shows as second order electrical.
And there may be other things that are not saved, for example I have the mid and tweeter in reverse polarity, but apparently the session file is not capturing or saving this.