I am back from a weekend of relaxing, watching the scenery and catching Lake Char.
And.....I opened my safe! A CGNer wrote to me that he had similar problems and gave similar instructions to what the fellow from Safety First did.
This is how I opened it:
The handle had some spring towards the lock direction - so I held the key in the "lock" (12 o'clock) position with my right hand while I reefed on the handle towards the lock position (counter-clockwise) until I bottomed out on the spring, whereupon I gentle turned the key. It worked - the safe opened.
I will be returning it to Costco shortly!
Thanks for the words of wisdom folks!