DPI blown call ?

[jstafan]

Hello all, first of all want to say I have learned alot these last couple of days since if found your fourm. I'm just your average Joe with a kid that plays youth football and thought that I new a little bit about the rules. after reading all the posts I have realized that I dont know what I thought I knew and the officials in my area arnt as bad as I thought they was. LOL. any way heres a call that took me a little bit to figure out.
Team A has the ball its 3rd and 38, final minute 30 of game, team A needs to score to tie game. A passes the ball, B gets flagged for DPI. The crew awards team A 15 yards its now 4th and 23. Team A exploads says it should be a automatic 1st down. I'm thinking the same thing. So when I get home I start to look up rules for DPI. I found that dpi carriers a 15yd penitly and also a auto first down. So I guessed they got that wrong. should have been 1st down. But couldnt figure just the 15 yds they assessed. Still not satisfied I kept reading and found out that you cant have DPI if the ball is behind the L.O.S. (which this pass was)So what I'm thinking now is that team B got the short end of that stick because it shouldnt have been called at all, let alone the additional 15 yds that got added to team A. So what do you all think about that one and is there any DPI that would be awarded just the 15yds?
Thanks