I know every place and situation is different, just trying to figure if
this is reasonable. (And someone's not pulling something over on a naive
home owner).

New to me house has a "sun room" built across the back of the house.
There are two separate sets of cement steps from the house to the room.
The steps are very awkward for me. I'm 5' tall, and the distance from
the door to the first step is like 9-1/2", and different on the other.
And since I have to step over a threshold just inside the door, it makes
the first step *really* big for me. I'm interested in having new "user
friendly" steps put in over the existing ones.

I had a contractor that I've used before look at them, just to build
plain wood steps over the existing steps, using Trex. He originally
quoted me $450 for the two, or $420 if I did it with plain wood. Then
the other day he came by and looked at them again and sent me an email
that he'd realized he couldn't do them as he'd originally planned with
stringers and needed to use a "box method" and that "there is more
material required with this method so the new price would be $750.00."

So questions - shouldn't he have realized what type of design he'd need
when he first measured the steps and quoted on it? And should the
difference really be $300 for additional material? And most importantly,
what would a reasonable price (range) be for two sets of steps (3 steps
each) in the Baltimore area? I was happy with the $450 although a male
relative told me he thought it was too much since it would "only need
$50 worth of material". I wouldn't be asking here about the original
price, but I'm confused by the $300 increase. (It's not the cost of
Trex, because the orig price specified a $30 reduction if he used
unfinished lumber).

Current steps -
http://smg.photobucket.com/albums/v7...kwardsteps.jpg