Apparently modifying the part.mass field only works once, or ?
Need to find a way to properly set the mass/etc of the editor part list part.
Need to find a way to properly update the mass in-flight (set mass directly)
Weird, weird stuff going on. MJ properly recognizes part.mass updates while in editor or flight. KSP engineer report does not. I likely need to cache the initial weight, and use IPartMassModifier to update the editor statistics correctly.
KSP recognizes in-flight part.mass updates appropriately; I previously had conflicts of multiple modules trying to set the mass inappropriately that was causing me to think it did not work.