Stones aren't an indication of malfunction - they occur during normal function of the gall bladder under certain conditions and will show up in most people. "Floppy" is the term used when the bladder can no longer contract properly to expel the gall. When that happens, depending on the degree of "floppiness," it can be a "gall bladder attack" that feels similar to a heart attack or some other hard-to-describe pain. HIDA will be used to gauge "floppiness" after stones are found via ultrasound to see if it's a long-term problem. Not many surgeons will remove the bladder without the HIDA to demonstrate the need for surgery.
Where are you practicing medicine? I've never heard of requiring a HIDA for surgery in the US for common gallbaldder disease
From my experience indications for choley is usually:
Symptomatic cholelithiasis w/ or w/o complications
Asymptomatic cholelithiasis in patients at increased risk for gallbladder cancer
Acalculous choleycystitis
Gallbladder polyps
Procelain gallbladder
Essentially, if you have gallstones and you have symptoms (biliary colic, actual cholecystitis, pancreatitis, choledocolithiasish, cholangitis), you should have it out.
HIDA scans are usually reserved for unclear cases where you might not see stones on ultrasound but you're concerned for acute blockage on the cystic duct or patency of CBD. In which case youre really looking for lack of Tec99 uptake into the gallbladder rather than this "floppiness" that you keep mentioning which isnt mentined in most of the guidelines as a legitimate surgical criteria.