So on Thursday I paid a visit to the dealer:
I went to Suburban Propane today. The 67.66 charge is the yearly minimum fee.
I've canceled my service, they are scheduling the tank removal. There is an $85.00 disconnect charge. The value of the propane in the tank will be applied towards the $67.66 and the $85.00. What a deal!
If I keep the tank to run it dry I'll still have to pay the two charges, so I elected to cut my losses and call it a wash.
There's around 80 gallons in the 100 gallon tank, I think the current price is $4.24/gal. That would be $340.00. We will see if they refund anything to me! I asked about heating oil, it's around $3.60/gal. I had a nice conversation with the rep., no reason to be nasty, I concluded the visit by indicating I was heating with coal now.