I am not an air conditioner guy but my local mechinacs cannot seem to get my 4430 air conditioner right. I put a new Sanden style AC compressor on my 4430 along with expansion valve and dryer. I cannot find anything telling me what the correct charge is. Some say 40 0z and others 56. Seems too be a big difference to me. Also it dropped from 27 to 22 vacum in about 17 hours. Should I chase a leak? Thanks in advance.