May not matter. Mine does not state hot or cold. I check it both ways and don't see much difference. I know my car has two marks one for hot and one for cold but the tractor shows very little difference when I check it.
That's a good question, one I will ask the dealer next time I stop in to say hi. I always check when it's cold but I eyeball it when I put it away and it always looks the same in the site gauge.