It appears that although there is automatic adjustment of the declutter level when raising the cruise level during pre-flight planning, changing the actual level flown does not do that.  Looking at this in simulator mode, when the flight vector would take the aircraft into CAS, it pops up with boundaries and a warning but once acknowledged, that goes away in its entirety and although the aircraft is still headed towards CAS, the boundary is no longer displayed.  In this case it was just after a turning point  and frequency change so there were other things going on.

My question is, have I got the system logic right here in that a decluttered level does not change if the aircraft actually flies above it and where an airspace warning is given, an acknowledgement removes the warning and the airspace depiction back to the planned declutter level?

Personally I always leave my declutter warnings set high as I often change my level once airborne.

John

Hello John, no, your summary is not correct. The actual altitude at which you're flying ALWAYS overrides any decluttering settings, with a comfortable margin too. Quite simply, it is not possible for airspace at your current level (or near it) to be hidden.

Warnings are separate from what is displayed on the map, so you have at least two separate chances to be aware of upcoming airspace.