I need a new mount because I'm going from an 8lb pj to a 40lb pj.
The Chief RPMAU is the way to go. They often pop up on eBay as new or complete units for not a lot of cash.
Unlike cheap mounts, Chief sells their stuff as separate parts. Typically, the mount, plus a universal projector interface bracket are sold together. So, the RPMAU includes the RPA Elite mount, plus the SLBU universal projector interface bracket.
The mount itself can be bolted directly into a ceiling, but it is designed to have a ceiling interface bracket (sold separately) and a extension column (sold separately) used with it as an option. The ceiling interface, most residential clients just think of a standard plate that attaches to your ceiling, but what if you have a drop ceiling? What if you have a cathedral ceiling? What about all the commercial ceilings that don't have any ceiling, or have concrete, or have an I-beam? They make custom ceiling interface brackets to suit almost any need. So, it's sold separately.
Likewise with the extension column. If you need a 2" extension, then that's what you get. If you need a 10' extension, then that's what you get. Completely up to you what is purchased.
This is the mount itself, without the SLBU universal bracket, you can see it includes about a 10" extension column, but not ceiling plate.
Item is in used condition.
www.ebay.com
This one includes the plate, but it only has 3 legs on the plate instead of four. You would need to pick up a extra leg (they can be bought individually online typically)...
Chief RPMA000 Black Elite Projector Mount Assembly 50lb Capacity w/ (2) Keys.
www.ebay.com
Extra leg...
https://www.ebay.com/itm/276008863069
That's the deal I'd probably go for since it gets you everything for under $100.
For the ceiling plate, I use 1.5" plumbing flanges from Home Depot. They work great. I spray paint them flat black.
For the extension column, I grab 1.5" plumbing pipe from Home Depot as well. Once again, I spray paint it flat black.
It saves you $50+ if you care to do it this way.