value of MAINTENANCE seems to be negated

[flyhoney]

When I test the value of MAINTENANCE in my Installscript, it seems to be TRUE on the first install and FALSE on uninstall, aka backwards of what is expected. Any idea why this is happening?

function MyFunction(hMSI)

begin                                                                 
    if (!MAINTENANCE) then
   	MessageBox("NOT MAINT MODE" SEVERE);
    else
    	MessageBox("MAINT MODE", SEVERE);
    endif;
end;

With my code above, I get the "MAINT MODE" message box on first install. I get "NOT MAINT MODE" when I uninstall.

I really hope I'm just doing something obvious and stupid.

[flyhoney]

Hmm, I am trying to access MAINTENANCE in a deferred custom action. Does this also have to be set using a set-a-property Custom Action?