Prefer not to have to exit the country as always a risk of being declined entry again. Maybe best to actually call into the immigration office and ask them directly.
this was my concern also. Will be going to Chiang Mai immigration to ask about this - as i have a five day holiday booked in Vietnam in January - by air!
I had the same problem re bank statements for past three months. What i did was upload the first one and then posted the others with the application. Nothing said and the required visa was issued.