It's not the identity of the truck which proves his guilt. If it is his truck it adds to the evidence, the reverse is not true.
What puts him there is the cheque and the knowledge of it the next day. He didn't need to wear gloves to hide his fingerprints - he left his calling card - he thought he could erase the ledger later but couldn't.
Given that Joey was going to discover the theft and that the cheque was deleted and hidden from Joey, it doesn't take a genius IMO to work out that the murders were premeditated and he may or may not have decided to use his own or any vehicle in his plan.
Evidence pointing to premeditation, in my opinion -
1. Being in the vicinity of the house on the 31st, 2nd and 3rd. Phone also dark on the 4th before 9.36 am, traveling northbound on the i15.
2. The 76 missing cheques taken from underneath the cheques in Joey's box, running on from serial numbers Merritt printed.
3. Custom account activity starting on the 1st and practice cheques.
4. Cheque drawn on the 2nd to set up a template for new normal course of business while Joey is not missing, but knowing Joey will discover it.
5. Opening a bank account on the 3rd, because he knew the days of receiving cheques he could cash were over.
6. Phone dark after his last call with Joey at 5.48 pm.
All MOO
I 100% agree with this.
It's the centre of the case. If the defence cannot explain the deleted backdated PM cheque on the 5th, everything falls apart for them, because it proves Chase already knew Joey was dead.
As you say, the problem was he couldn't delete the activity log in QB.
He needed all the cheques to be created before the 5th, to fit with the story he told Dugal. Backdated to the 5th wasn't good enough.
It's that greed that sinks him.
And ironically if he hadn't backdated the cheques - the case against him would be far weaker.