Time to Replace Central AC?
Is it time based on the power consumption? I will try to be polite but Hell No. when your system is running at full load and hot the power may get close to RLA , RLA is like FLA for motors. If they are drawing less they are not fully loaded. 
Having a worn out compressor could cause a lower power consumption but then electrical parts would not be overheating. If your system is leak free it sounds like it is keep it clean and you may get another few seasons out of it. R22 is obsolete and cost an arm and a leg at the time your system starts under preforming, then a compressor replacement could be an option but this is NOT a diy job, the Freon would need to be removed in a recovery system the old compressor cut out and replaced with a new filter dryer then recharged with the old r22 , just note if there is a leak it will be cheaper to replace the system as R22 is going 100 per lb and up, but it is still available but expensive. Your system takes 10 lbs and even if you need to change the compressor the Freon is still good. But you may need a few lbs to top the system normally less than 50% for a functioning system in my experience.
If you see your power bill jump, compressor starting to run all the time and may not be cooling as well with the same temps as last year this is when the system needs more than a annual check up.