John Deere 4930 air conditioner not cooling

I've got a 4930 that the air conditioner will freeze you out of the cab at idle but at WOT it doesn't seem to cool the best. I have washed out the entire cooling package and replaced the cab filters. At idle the low side is at 30 and the high is 150 on an 80 degree day. At high idle the low is at 20 and the high is at 160. Doesn't make any sense to me whhy it won't cool at high idle. Any thoughts?

John Deere 4930 air conditioner not cooling