Interesting, so the OP is able to process his application whilst in Thailand? perhaps thy have changed it since 10 days ago but i could not complete the app or get access until I was in Lao, once that app is done an automatic payment reciept should be ready to download in the app/account, take that and 10k cash to Vientiane between 9-12 Mon Friday, once it is received there, the processing begins.
I applied on sunday night like 4am in the morning as the visa access I believe was denied unless you are IN the country. So I processed that application very early monday before they opened anywhere, printed off the reciept, paid at the consultate, got it by wednesday. Can be done in 3 business days. You have to pay between 9-12 on each day. no good if late, wait an extra day etc.