Board Thread:The Last Sovereign Discussion/@comment-29984007-20200520171144/@comment-36170150-20200601145647

The Chapter 3 EXP boost works based on Simon's level when you finish the Ardford section and it affects the entire party, it is more meant to be a consolation prize/catch-up mechanic for underlevelled players, you could potentially try to game it a bit by making Simon specifically be underlevelled so the rest of the party have more EXP than they are supposed to have, but that's probably counter-productive since most EXP checks are made based on Simon's level.

Anyway, the exact mechanics are like this: If Simon's level is 23 or lower, the entire party receives 60,000 EXP, for each level higher than 23, the boost is reduced by 5,000 EXP; so if Simon is level 33 it will be giving 10,000 EXP, if Simon is level 34 it will be giving 5,000 EXP, and if Simon is level 35 or higher (I think this might be impossible) there will be no boost.

There could be an edge-case where you might want to miss out on some potential Simon EXP on purpose if otherwise you'd just barely level up at the end of the Ardford section, but looking exclusively at Simon's EXP, the extra EXP you'd get after the level up would have to be less than 5,000 to make it worthwhile.

Optimizing Simon's route past a certain point is kind of splitting hairs, since you can only use those extra days to gain a pittance of extra EXP on Simon and/or Nalili, but I remember there were some things that you could optimize over the guide to get a few extra days: You can choose to have a short talk instead of a long talk with Nalili when entering her bedroom (does nothing but give more RP which is excedent), you can reduce the ammount of times Simon uses the brothel, etc.

The options to gain EXP from extra days during Simon's route work like this:

Train Nalili -> Nalili's EXP +500

Spar with Nalili -> Simon's EXP +150, Nalili's EXP +250

Simon trains alone (with the succubus in the armory) -> Simon's EXP +250

Long story short, if its worthwhile or not gaining extra EXP on Simon during Simon's route depends on how much EXP you're finishing the Ardford Summit with, but it could be counter-productive if it manages to barely push you up a level.

EDIT: Take this with a grain of salt since this is based on my own optimized playthrough, but without getting extra Simon EXP during Simon's route, and if I had Simon in for the Unforge bonus fight (in my run I don't get essence shielding first so Simon can't be in that battle), I would have been 2,702 EXP short from getting to level 34 at the end of the Ardford Summit, so as long as you don't get more than that during Simon's Route (would take at least 11 days of Simon solo training so very unlikely), it should be fine to put extra EXP on Simon instead of Nalili.