Can I leave Thailand on the last day of my tourist visa extension and apply for a multiple-entry Non-O visa in Laos?

Hey guys....just want to thank for all your help....i would be lost....

My extension on my tourist visa is stamped Sept. 01 2019.....its stamped....can exit I Thailand on that date...ill be going to Savannakhet Laos...ill exit Thailand and do a Laos visa on September 01 2019 early morning ...go to Thai embassy in Savannakhet on Monday Sept 2 2019....i know Monday's are no good....then apply for a multiple entry non o based on marriage...im not overstaying for Thailand...i am exiting Thailand and doing a Laos visa on the date my extension is stamped September 01 2019...dont know if that raises eyebrows...dont know if people ever do that....so when I do my multiple entry non o based on marriage on Monday Sept 2 2019 in Laos I would be on a Laos visa...i should be fine right....i can leave before that...but like anything else...something could come up....where I might have to switch dates....just wandering if I can do that and it won't affect my multiple entry non o based on marriage when I apply