Thanks, it seems clear to me that when it is gifted, the land office will use the official (probably Treasury Department's) appraisal of the condo as a calculation basis to levy tax and fees.
What I wasn't sure of, was based on what value actual money needs to be transferred in the scenario of gifting from a Thai to a non-Thai spouse or if there needed to be money transfer at all.
So these situations may occur in terms of money needed to be remitted from abroad:
1. nothing,
2. full amount of the original purchase price stated on the Sale and Purchase Agreement to Thai spouse--> FET form for documentation,
3. full amount of the (virtual) official appraisal value to Thai spouse --> FET for documentation
As to @Robert Paulson it seems #3 is the case.
For @soi3eddie 's scenario it seemed an "agreed value" was put down which seems more like a straightforward purchase situation with a price tag rather than a gifting situation.