...what would also make sense resolution-wise: LSB seems to be 0.5mV (measured) which is in line with wibauxl's theory ((2.75-0.55)/4096=0.537mV). This DAC behaviour -and te lack of it's documentation- is a little odd to my opinion, but at least there's an explanation that makes sense.
MANY THANKS FOR ALL YOUR INPUTS!!
andy_g