Honestly - a group in their teens hasn't lost much AA really - just as easy to /lock all your 17s and just do any quests you missed - if you didn't miss any quests no worries - just /lock and keep going - you'll end up with a good handful of AAs

There are really several ways to maximise your AAs when you think about it:
- /lock at 10 - with the aim of getting 100AA at 60
- /lock at whatever level and go back and do all the grey stuff - just as valid if your a grinder - i.e., race to say lvl 40 via dungeon grinding, then go back and do all the grey quests
- /totally forget about it with the understanding that the character won't be the best in end game dungeons - which is ok if it's 1 maybe 2 chars (not the tank), after that, it does effect overall DPS which means the entire team starts to clear dungeons slower - doing it this way means you will have to visit all the old zones which can get boring doing grey stuff

It's just more simplier to get as much AA as you can whilst you are leveling - this way you also get to see the majority of the game content