Where did the fan go? How high is the roof?

A friend had two layers of roof removed and a new roof put on,
House was built about 1969, and had the second roof put on about 1990.

From the outside of her house, she could no longer see her roof fan!,
so she called the company (one she has used before with great
satisfaction) and someone came out with a ladder, went up and took a
cell phone picture of the fan.

He told her that it was lower than it used to be because two roofs had
been removed.

(Now I couldn't see the south side of my roof, and by the time I put a
new roof on, it had curled (the north side which I could see still
looked fine) ). But I thought a second roof would only be about an
inch thick. An overlapping layer of tar paper and the overlapping
layers of 3-tab shingles. No more than an inch?

My friend is under the impression that a new roof includes a new layer
of plywood, in addition to the original plywood. Of coure I figure I
know more about home repair than any female (except Norminn) so is my
record still perfect?

And furthermore, why would adding a second roof raise the fan. The
roof would go on over the fan's flashing. (I think the fan was
installed when only the original roof was on, but does it make any
difference?)