See this statement on here all too often. See below and form your own conlusions......
The Prohibition on Venting
Effective July 1, 1992, Section 608 of the Act prohibits individuals from intentionally venting ozone-depleting substances used as refrigerants (generally CFCs and HCFCs) into the atmosphere while maintaining, servicing, repairing, or disposing of air-conditioning or refrigeration equipment (appliances). Only four types of releases are permitted under the prohibition:
1."De minimis" quantities of refrigerant released in the course of making good faith attempts to recapture and recycle or safely dispose of refrigerant.
2.Refrigerants emitted in the course of normal operation of air-conditioning and refrigeration equipment (as opposed to during the maintenance, servicing, repair, or disposal of this equipment) such as from mechanical purging and leaks. However, EPA requires the repair of leaks above a certain size in large equipment (see Refrigerant Leaks).
3.Releases of CFCs or HCFCs that are not used as refrigerants. For instance, mixtures of nitrogen and R-22 that are used as holding charges or as leak test gases may be released.
4.Small releases of refrigerant that result from purging hoses or from connecting or disconnecting hoses to charge or service appliances will not be considered violations of the prohibition on venting. However, recovery and recycling equipment manufactured after November 15, 1993, must be equipped with low-loss fittings.
As I read from 608... NO low loss fittings required on manifolds just on recovery/recycling equipment.
The EPA realizes we are always going to have a little loss, they just want us to keep it to a reasonable minimum and to never just 'vent' for convience.
I like the ball valves. I always seemed to tear up the oring on my low loss fittings. The other hoses freeze up my hand when unhooking the high side. I always release the pressure when I'm done charging. If you leave your gauges pressurized it will mess them up from what I've been told.