How about this, much simplified:
> Level 6: Deceptive Summons When you summon a demon or devil, you learn the fiend's true name.
> Level 6: Safe summoning When you lose control of a demon or devil you summoned, you can use your Reaction to dismiss it.
> Level 10: Fiendish Legion When you use a Conjuration spell to summon one or more demons or devils, you can summon one additional creature of the same kind.
> Level 14: Unrestricted Conjuration When you summon a demon or devil, it cannot break free of your control and is friendly towards you for a number of rounds equal to your Intelligence m…