My wingspan increased

There is a time in every man's life when he realizes he knows his body so well it cannot surprise him anymore, at least that's what I thought. I was wrong. I've been hitting weights for over a year now and I noticed that besides predictable changes(I'm talking mostly about GAINZZZZ) my wingspan increased. I'm 6'1" and I'm not Matthew McConaughey (who has short arms in case you live in a cave), my wingspan used to be about 6'2" and now it's 6'4". My height hasn't changed since I was 15 which makes it 10 years without getting taller.
I suppose it's mainly due to shoulder stretching even though I can't recall having stiffed shoulder muscles before.  Pull-ups are the biggest part of my routine. And perhaps all that hanging made my wingspan bigger. Also, I think deadlifts have a great impact, the concept itself, lifting something heavy off the ground, makes my arms longer)
The bottom line is I am not sure why it happened, but it happened. And since I play a lot of hoops, it comes in handy)
There is an interesting page at http://www.draftexpress.com/ called NBA pre-draft measurements, according to which the average wingspan for my height among draftees is 6'5.4" and among PGs only it's 6'4.5" with an average height of 6'0.61'', meaning I have the average PG body despite being an Asian dude. Jeremy Lin, by the way, is 6'3" in height with a 6'5" wingspan.