FREON

hi..i have a honda accord 91" model with 4 cylinder engine, my condenser have a small leak so my mechanik friend fix it and put freon on it, the thing is the a/c is not that cold when it was before, i just observe that while he's filling the freon gas on it he didnt turn the freon gas cylinder upside down while filling it, coz i saw one of the mechanics whos fixing another car turn the cylinder upside down while filling freon,,my question is;do you think its normal to turn the cylinder upside down?or its the wrong procedure
?tnks