Hi @j_bishop
The height returned by the GetLastLiquidLevel is the detected liquid level height (in mm) relative to deck coordinates of the instrument. Meaning that if you obtain your teaching values and substract these from that height, you receive (I presume) this 31.4mm results. I also presume your LIQUID_LEVEL_GetLiquidLevelHeight SMT does this by obtaining the XYZ coordinates and substracts them from these.
That doesn’t necessarily mean that this is the correct height. Check for your labware definition if that height is allowed.