There has to be something wrong with your readings (Pre or post). What did you use for Pre-Boil readings? I don't see that in the post.
And, as a matter of fact your beer does increase in gravity while it is boiling. The water evaporates and leaves all of the sugar in place to create a more dense wort.
Something is really fishy.
"There is no strong beer, only weak men"
"Pretty women make us BUY beer, ugly women make us DRINK beer" - Al Bundy
"Give a man a beer, he'll drink for a day. Teach a man to brew, he'll be drunk for the rest of his life."
Primary: Viking Metal, Berliner Weisse
Kegged: Oaked English Mild, Modus Hoperandi
Notable Empties: Oaked Black IIPA, BBK I, Red IIPA, Burning Bush, Apophis "The Destroyer", Vanilla Porter
On-Deck: Hobbit Ale, The Titan BW, Ale of Olympus