Certification of bulk 'high density plastic pellet' deliveries

My company is trying to become AIB certified and we manufacture extruded food contact packaging.  Here is my question:  The only bulk material we receive is high density plastic pellets which is directly fed from the truck to our silo via air pressure and a flexible 4 inch line.  Do I still need records of tanker wash tags, prior load verification, and seal verification.  Or can I get a statement from our vendor stating that the only thing the truck carry are plastic pellets. Basically what im trying to ask is given this scenario, would getting a letter of guarantee or such from our vendor be sufficient in the inspectors eyes given what we manufacture, because we don't directly handle any food.

As you describe above, a simple declaration by the supplier will be adequate but this statement must be truck specific. If the vendor uses the truck to transport other non-virgin plastic pallets like recycled plastic pellets, keeping records of tanker wash tags, prior load verification, and seal verification must be kept. Further to this, it all depends on the auditor. Some will accept a declaration by the supplier, other will insist on the everything.

Funny, we have railcars (about 40 on any given day) which pump to silos. i have never been asked for a wash tag or anything. We rarely use a tanker truck but one would think, after reading this, we would need a wash tag or statement from the resin suppliers for railcars. Does anyone disagree the need for railcar statements?