End of timed warmup question?

[SCalScoreKeeper]

Ok here's an interesting question from my matches tonight-
In Southern California we set the clock for warmup as follows:5,6,6,3 mins to make up our 20 minute warmups. His question was what is considered the end of Warmup for the purposes of submitting lineups-Either the end of our second six minutes or the three minute period? My answer, his answer, and my official scorekeeper's answer was that it ended with the second six minutes and that lineups must be in by one minute to go in that period! Were we right? casebook/rulebook citations please!