The depreciation value is based on the "lower" of what you originally paid for the property plus the cost of any property improvements, or it's FMV on the date placed in service... whichever is lower. Typically, your original purchase price will be the lower now-a-days. The "taxable value" does not come into play at all for depreciation purposes.
Now the program will use taxable values for the purpose of determining what percentage of your cost basis gets allocated to the land. That's pretty much it. Tax valued as determined by your county property appraiser isn't reported anywhere on your tax return.
