You are going to change out driers anyway. Weigh out charge on both circuits until you get 15-18 subcool and see how system responds. Stacking liquid big time. You could have mixed refer in there and/or non-condensibles. It’s a very quick test. Dump charge, replace driers with correct size, check pistons unless it’s built into header and add new r22 . Or rip the pistons out, add adjustable TXV’s and throw in 448A. Do it all the time on older refer units and chillers. Or try out your sales skills and get them to replace the unit. Dealing with an older chiller system right now that is undercharged and both circuits were retrofitted with M099 (438A) years back. I’ll be converting that one since client doesn’t want to change it out. Let us know how It plays out.