Substitution question

[Nevadaref]

From the 2003-04 POE:
H.If a substitute from the non-offending team or a substitute from the offending team for someone other than the disqualified player reports to the scorer during the wait for the required substitute, they may enter the game. (3-3-1d)

I.A warning horn shall now be sounded at 20 seconds if the required substitute has not reported to the scorer’s table. This is an indication to the head coach that a substitute should report immediately (2-12-5). This warning horn does not have the same substitution restrictions as a warning horn for a time-out (3-3-1a); other substitutes from either team may still report and enter the game until the ball is about to become live. (3-3-2)

*Note that back in 2003-04 a HC had 30 seconds to replace a DQ'd player or a player directed to leave the game and the warning horn was at 20 seconds. This has since been changed. The current times for 2008-09 are a 20-second replacement interval with a warning horn 5 seconds into it.