Need help with self-leveling compound under bath?

Any thin-set or level-set should work but, I, after rebuilding my joists and putting in a new floor, I also put in 3/4 inch plywood over the floor to distribute the weight, then I measured the area of the tub, put it in and draw around it, then I put about four bags of thin-set down and worked the tub into it. This of course was after I made sure I had all the lines level and everything was in place. The tub now sits in about 160 pounds of thin-set and is as solid as a rock, no noise, no shifting. I believe if your going to do a job, do it right the first time. My son-in-law wouldn't listen, now whenever the kids take a bath, it sounds like someone on drums upstairs.