TW, You are a bit mistaken about the Palazzo and the Venetian sharing the same casino, The only thing they share is the same owner.
As you most likely know .... there are two very different casinos ... One in the Palazzo and the other in the Venetian and you offer great advice about contacting the Slot Host or the Pit Bosses to inquire about getting your final bill reduced.
Of course that's mainly done for the big time gamblers but just last month my three night hotel room stay was turned into a three night comp]'t vacation because I merely asked politely ... and I am a cheap ass gambler ,,, but on this occasion I happened to win a few more bucks than I usually do and as a result I played longer and they upgraded my player's club card so now I get a free gift every week plus more comps than I can ever use.
This all happens at Boyd's Orleans which is off the Strip.
The Orleans and the other locals' casinos offer us Las Vegans comps in the form of cash, booz, food, room nights, gifts, etc. that I save to give away as Christmas presents just to get you inside so the place will look crowded to the out of state visitors.
Try a local's hotel/casino on your next trip. You;ll be seeing a major difference.