Question on multiplex sampling / simultaneous sample & hold

Hello together,

I own a NI USB 6211 board which works very well. However I am trying to understand how exactly multiple channels are being converted from analog to digital. Therefore I drew two pictures with the way I understand multiplexing and simultaneous sample & hold. It would be great if you would check it and correct any errors I made

Thanks

and 

Can I find the exact conversion timestamp with the 6211 device?

Best regards