All true (possible exception of the flat rate issue.)
If your tank is not completely empty you are getting screwed by paying for propane you are not getting and if you ARE empty they may (and most likely will) charge you a flat rate for "purging the tank of air."
Swapping an old or over-age, rusted, covered with BBQ drippings, 20 pound propane tank for a new, painted, hydro-statically tested, bottle is still a "good deal."
A new tank can cost 50 bucks empty, then you have to pay for "initial purge" and a fill.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW