In my area 'flashgas' (liquid refrigerant in LL evaporating into gas before the metering device) is not common... unless the lineset is run next to the rafters... I have seen the LL along the rafter purlin support... dumb idea IMO.
If the LL is close to the attic floor... usually this is not an issue. If it is high in a HOT attic... then probably a good idea. If it is out in the sunshine... then IMO definitely a good idea.
Regardless... I would not expect a big drop in elec used... just one of those little things which when paired with many other little things might show a noticeable drop in energy usage.
I remember Houston TX... in those sweltering attics... I think I would.