Thank you very much for your note and your code. Though I think "changed around" is a fairly mild way to describe what they did.
I issued version 0.101 around August 3 2014, which accesses the same web site your code appears to access.
I take it you code is based on Geo::WebService::Elevation::USGS version 0.009? After the long weekend I would like to compare your code in detail to the code you based it on, and see if there are any ideas I can, er, borrow.
In the meantime, I am marking this ticket patched, because version 0.101 passes the test suite. I will not close it until I have looked at your code in detail, and you have had a chance to comment.
In the meantime, I appreciate knowing someone finds my code useful, and is willing to help remedy its defects.