Enforcement Question (High School).

[wmena]

Team A has ball.
2nd and 10 at A44.
Rush 5 yards to A49 yard line.
Penalty on Team A (Illegal Block-15 yrds).
Ref drops flag A40 (which is behind orig line of scrimmage).
Ref walks ball off from A40 back to A25.

Is this correct? Since the penalty happened behind the line of scrimmage, isn't the enforcement spot the original line of scrimmage (which was the A44)?
I also assume that for statistical purposes, the play does not count (ie... no rush stats).. correct?

Can point me to the rule that handles this enforcement, I'd appreciate it.

Is the outcome different between HS and NCAA?