Greg,
Make sure the Kubota coverage is for replacement cost and NOT ACV (actual cash value), or has a coinsurance clause. This is a good practice for any type of insurance you buy for your house and/or any property you own. Our minivan, which is 4 years old and has 100K miles on it, I have it insured for $27K for all coverages. In case you are wondering about this the coverage is called agreed amount coverage. I pay an extra $100 a year. The AVC is more like $12-15K on the van.
The difference being with ACV they will depreciate the value of the tractor based on the age of the tractor. With replacement cost you get what it would cost to replace the tractor, minus your deductible. Also the Kubota insurance is only for the life of your loan, when you get done paying you have no coverage.