I flew from the UK to Laos in January (via transit in China), and entered Thailand via land border from Laos, in January
I extended that stamp, then did one border run in a van to Cambodia, then extended that, so I can stay until early May
So i've only done one 'in out' trip in a van.
But it seems it's not about two 'in out' trips in a van, it's two visa exempt entries by land, ok thanks for the info