One thing the jury could possibly be thinking of (just want to play neutral for one minute...LOL), is that if it was pre-planned, why didn't they get the saw and the things like plastic, bleach, and stuff, before Laura got to the apartment.
But they have to remember Boz's words that premeditation doesn't mean planning months or weeks or days in advance...it just requires that they thought about what they were doing (killing her) before they actually killed her.
There is evidence of that - Laura coming mid-week, Grant's idea for mid-week visit, note written ahead of time, etc..
So maybe Amanda was telling the truth when she told Bearkat or Baraket or whatever the name was, that they didn't plan for it to happen that way.
Maybe, initially, they only planned to strangle her - no blood involved.
Maybe something happened, and they had to stab her, or just decided to stab her (change of plans).
Blood involved.
Throw her in the bathtub.
Couldn't take her out b/c scared of blood getting places where investigators would find it.
So they decided they had to cut her up and put her in coolers, in order to contain the evidence.
I am thinking maybe the jury is stuck on this pre-meditation aspect of it.
If they can just get around planning the "perfect" crime. There is other evidence that it was pre-planned.