Night Lords Query (HH) (some spoilers)

[Bedlam]

I've just finished reading the first Heretic and is seems to contradict the audio story the Dark King.

In the Audio Konrad Curze has a fit attacks Regal Dorn, gets locked up, kills his guards and leads his legion into Renagadehood and destroys his home planet. No time frame is given for this but I assumed it was some years before the Heresy.

In first Heretic the Night Lords and Curze are one of legions making up the reinforcement wave on Istvan V and took place in the massacre there.

I don’t see how the two accounts can fit together, if the night lords had already done renegade they are not going to be called by the imperium to help defeat Horus (I suppose its just possible they might have been told all is forgiven if you help us but there's no sign that the loyalists doubt their loyalty at all). If the drop site massacre had already taken place then Curse isn't going to be locked up for hitting Dorn when he's already helped in the destruction of 3 legions.

Does anyone know what the 'true' events are supposed to be or how the two separate stories can be fitted together?

[Imperial Overlord]

Lexicanum (which isn't canon) has the events fitted together this way:

Reinforcements to replace the Night Lords that fell in battle were selected from the population of Nostramo, but in Night Haunter's absence, the population of the planet collapsed back into the corrupt and decadent ways that had prevailed before his arrival. The ruthless criminals were the only ones to remain healthy and strong, so it was these men who were recruited for the Legion. Night Haunter began to lose some of the control he held over his Legion, and the visions that plagued him increased in both lucidity and quantity.

Learning of the fate of his homeworld, Night Haunter tried to confide in his brother Primarchs, but had never been close to them in the beginning, and their reaction was less than favourable to his claims. He attacked Rogal Dorn of the Imperial Fists before taking the Night Lords fleet to Nostramo. A few Imperial pursuit craft arrived just in time to see the Night Lord's laser batteries firing into the hole left by Night Haunter's arrival decades earlier. Nostramo's core overheated and the world exploded.

Night Haunter's terrible acts caused him to become susceptible to the whispers of Chaos. The campaigns of the Night Lords became less justifiable, terror campaigns leaving a trail of devastated worlds across the galaxy. Night Haunter no longer crusaded in the Emperor's name, instead fighting only in the name of death and fear. Eventually, the Emperor was forced to order the recall of Night Haunter to answer charges laid against him and his men. But before the Night Lords reached Terra a new crisis erupted...

That seems to make some sense. It's conceivable that the Night Haunter was distant enough and given enough rope by the Emperor that it was some time after his destruction of Nostramo and after a number of other excesses that the Emperor finally called him to account. If Curze had issued repeated warnings about the Warmaster sliding into Chaos its conceivable that the Emperor thought that in this matter he was reliable, especially if he didn't believe the charges against Curze were true.