System #2-5 and #8-16 need 1-2lbs of 410. System is slightly low on refrigerant. Saturation temp on both the low and high side are below expected temperatures. Outdoor temp of 57* should result in a saturated temp of 42-37*. Actual temp was 29*. All above systems were identical with regards to temp charge. Most likely reason being a seasonal maintenance plan where the charge was checked using a manifold with long hoses. After enough pressure checks / maintenance checks refrigerant has been slowly removed inside the technicians hoses. Systems have been in place since 2017. System #6- needs 4lbs of 410. System is low on refrigerant. Saturation temp on both the low and high side are well below expected temperatures. Outdoor temp of 57* should result in a saturated temp of 42-37*. Actual temp was 15*