Generally unless the setup is obviously 'broken', it would be even less than that..
There is some "late mail" on this-
Sun morning-somewhere in the UK...
I have been stuck at 2:02.3s for about 60 laps.
One of my FSR team mates who is particularly good at sets, shared a set with me.
My first hot lap was 1 sec faster, within 5 laps I had 2:00.93 sec.
Thats about 1.4 sec improvement on a set I had been tweaking quite a bit (version 7 or 8).
So I have now have to disagree with (or update) my previous opinion! and subsequently yours Lazza which pains me as I have great respect for your knowledge.
BTW I know what you mean about going back to a previous set and being as quick or quicker. I call it sanity checking a new set, so often all the lappage makes you faster and you are faster with the original one. Always worth going back and checking.
I can reveal that the set was more oversteery than mine but controllable in a slide.
Another of my team mates is in the 1:57 bracket with that same set. So we can safely say from here on it's about skill!.
I am loving this event, such a great eye opener and learning curve.
PS: dont stop buying my set up guide its still really good (just lucky my team mates collaborated on it).