@Tod ********
i did not do full bounce, but had motorbike trip to Malaysia land boarder, then from Langkawi (MY) boat to Ko Lipe (TH) (just asked VISA pdf as they did not see in the system), then went back to Langakawi and motorbike back again TH via lang boarder and there as well was fast, only PDF + passport. Sure it is free.
I made a smaller laminated visa pdf version which fits into passport. They were not thrilled, but accepted as all info were there just smaller and in 2 sides :) I do travel too much in and out...
Btw they do see the previous DTV arrival reasons' stamps...
No idea why their boarder controll system does not automatically flag which passport has what (active) VISA. Although they knew about all my other country passports..