Hi guys,
I have never heard of ASIS so I'm not sure how compatible it would be with Balanced Magic, but I can offer you a little insight as to how Balanced Magic works (as of version 3.01).
I created two new perks, BalancedMagicCostOffset and BalancedMagicScaler, which I then added to the player actor (they are not on any perk tree, I just went into the Player Actor SpellList and added them to the other perks the player has by default). CostOffset does just that - it makes the low level spells a little more expensive and the higher level spells a little less expensive since cost no longer scales down as your skill increases. Note that NPC costs are calculated with separate gameplay settings, so if you want to apply the changes to NPCs, you'll need to adjust the NPC settings or they'll be able to spam high level spells far more often than they should! Scaler does most of the work - it handles all of the automatic skill based scaling, as well as the bonus to casting cost for unarmored magic users.
As far as I can tell, NPCs use a very limited set of perks, and generally do not use the novice/apprentice/adept/expert/master perks. I used these perks for some additional scaling that players may choose to spend their perk points on, so for NPCs to get the full effect, they'll need to be added to the mage-y NPC actors.
If you get everything working, I'd love to see the merged result!