Air Conditioning - Loud start up noise/ high pressure?

A/C guy came out today for this on going problem of the A/C making a loud grinding type noise when it started up, which was louder and longer in duration the longer it sat between cycles.

He said the pressures were high... Said it was 80/225 and he brought them down to 70/200. Does this sound right. Its a Goodman 5 ton 14 Seer with matching coil.. And that these high pressures may have been causing the compressor to make this loud noise. Not really making the noise right now but will find out later as it runs through cycles.

One cannot tell if the system is properly charged by pressures alone. Goodman has always specified superheat as the correct method to check the charge in their systems. This is applicable to systems with a fixed orifice. Expansion valve systems should be charged by sub-cooling.

Grady is 100% correct. They cannot go by pressure to know if it's properly charged. Overcharge will cause noise like that but they need to do it right.

I guess that was it too high pressure does not make that loud grinding sound now. I think the tech was cheating because when he had me go in to turn air back on a few times I could the sound of freon being released. He did this a few times and ran air about 15 min in between. Isn't he suppose to not release this freon at all?