The unit comes from the factory "Pre charged" with enough refrigerant for a matching indoor coil & 15' of properly sized refrigerant lines.

This is very vague in itself as a properly sized indoor matched coil could hold more refrigerant than another one that is also properly matched. (EXAMPLE: 3 ton Goodman indoor evaporator coils) - CAPF3636B6 & CAPF3636C6. The B stands for 17.5" wide and the C 21" wide. The C width coil is actually bigger than the B width version. As far as refrigerant is concerned, there isn't much difference, however there is a difference.

Next, there is whoever shot refrigerant in at the factory during the manufacture of the condensing unit. Trust me when I say some units come with less than the unit states and some come with more.

Ok, I'll get to the main points I have on this.

I agree with the comment stating this is one reason Goodman gets a bad reputation. The people putting it in are often times not the most skilled HVAC technicians or they are just out to give it to their customer. One of the two, no other way to put it.

When a system is started up nothing at all should be added or removed for several minutes. Indoor temperature and indoor wet bulb temperatures should be recorded. Outdoor temperatures should be recorded. (I'm assuming the technician has already confirmed that the indoor coil is clean, the indoor blower housing, wheel, & motor are clean, the air filter is clean, and there is no furniture on or in front of supply and return registers throughout the home). Good, those all checked out!

with the recorded temperatures that were taken the technician should be reading the manufacturers installation and start up information & checking the systems super heat & sub cooling. Each time some refrigerant is added or removed from the system the tech should give the system several minutes to allow the pressures to stabilize wherever they are going to and check where those superheat & subcooling measurements are until the system is perfectly, (near as perfect as possible), dialed in. Too little refrigerant & your starving the compressor, causing it to not perform as well as it was designed, along with several other undesired results. Too much refrigerant & your slugging the compressor with liquid refrigerant it wasn't designed to receive, as well as several more undesired results.

Note to homeowners: Quit worrying so much about the brand you buy & focus that effort on what contractor you hire to install your AC system!

just my 2 cents.