It's expensive if you go into the tunnel and say, "I want to test changing the height of my front end" and then it turns out that it takes 20 minutes to change that front end for each 10mm increment you want to test and you end up with 2-3 positional changes in an hour.
You thinking up wanting to change your front end was free. The very limited results you get from that in a tunnel were definitely not free.
It's expensive if you go into the tunnel and say, "I want to test changing the height of my front end" and then it turns out that it takes 20 minutes to change that front end for each 10mm increment you want to test and you end up with 2-3 positional changes in an hour.
You thinking up wanting to change your front end was free. The very limited results you get from that in a tunnel were definitely not free.