Continuity mistake: The candles on the cake at the party change height a few times during the sequence.
Continuity mistake: After Combo is killed and Skinny leaves the operation, Jesse and Walt are in Saul's office, explain what happened, and they start bickering. From a side angle you see Saul lean forward in his chair as he yells "Guys guys!" to try and stop them. It then cuts to an angle showing Saul from the front and he's suddenly leaning back in his chair, not forward.
Answer: Saul is a criminal himself. It's not past his capabilities to forge some documents to show the 857k is available.
Ssiscool ★
Forged documents by Saul is most likely the correct answer.
The_Iceman