Franklyn

Aren't you over complicating this?
If your annual dosemitry and timer calibrations are up to snuff, you already know that the "correct dose" is being delivered by the irradiator. What you want to do is validate, upon receipt, that each new lot number is functioning as expected.
There is usually an indicator shipped with each box/lot - first document that the indicator documents the received stickers as valid for use.
Now put a sticker from the "old" lot number and a stick from the "new" lot number on a unit (this can be done during normal workflow) and nuke em. They should compare favorably, if they do the new lot has passed receipt verification and If they don't the new lot "fails" and needs to be returned to the vendor or some other corrective action needs to be pursued.
Your dosemitry mapping should very precisely tell you where the radiation is being delivered and the physics of it are concrete. If you have a calculator and a calendar you can perdict dosage for years in the future. All the "Rad Sure" stickers due is give you a visual clue that you have, indeed, irradiated the unit so that you do not irradiate it again in error.
At least that is my take on it. I am at a registered facility (not a licensed facility) so your requirements may vary.

I looked at the Nordion very closely at the 2007 AABB Txpo in California. The suitability of the instrument really comes down to your volume. It is relatively large, as a current total volume of 1.5 Liters and a 5 minute cycle time. The instrument uses two X-Ray tubes (top and bottom) and the tubes are each warrantied for 2000 hours of service. The device needs a water feed on a dedicated cooling loop (per code for water cooled devices in our area). The device has a 3 to 5 minute warm up period from a cold start and is not intended for continuous use. So, you have a warrantied period of 24,000 cycles on the tubes but could/should see more. If you average two products per cycle, that is 48,000 products within the warranty period. Your mileage may vary.
Franklyn