Seems perfectly normal, Thailand needs travellers like you GL just keep a watching brief as they were mulling over reducing the 60 day visa exemption back to 30 days but I would be surprised if they implement that..its like going backwards and unproductive
Best do 6 months, the soft options are likely to be looked at more closely going through immigration in the future but I think they need to be sensible about bit they need long stay visitors contributing daily to the local economy.
They just need to concentrate on weeding out those that shouldn't be in Thailand for various reasons. I welcome a clean up
Your stamp for dtv is 180 days if not you need to go back to airport immigration and get it corrected. Makes no difference what date you put to depart on your tdac. You can put any date or leave it blank. You don't need to show a return flight with a dtv.