yes, the inclinometer is accurately calibrated in our factory before being shipped, however, whatever MEMS sensor is influenced by thermal mechanical stresses like the one that happen during the soldering on the PCB of the final product. The necessity of performing a further calibration at the end of the line depends on the accuracy requirements of the applications, but when such requirements are on the high side, you can't practically skip the calibration after soldering and assembly of the final product. What differentiate a low cost accelerometer from an high performance, higher cost inclinometers is mainly the stability and repeatability over temperature and overtime which is something that you can't achieve on low cost accelerometer, even performing more complex and costly calibration over temperature in the factory
