Is it best to have the plumbing placed in the attic or slab for new construction. Would the expenses equal out?

Is it best to have the plumbing placed in the attic or slab for new construction. Would the expenses equal out?

Up and down the West Coast Of Florida all of our buildings are on slabs. We rough in under the slab instead of overhead in the attic.
The three main reasons are;
1) The expense factor. It takes more time and material to pipe overhead.
2) The time factor. When we loop our water in the slab at the same time we rough the drainage all of the mains, branches and manifolds are already in when the framers start. If we pipe overhead we have to wait on them to finish. This adds labor expense and drags the job out.
3) The leak factor. If a leak in the water pipe develops where would you rather have it. Under the slab out of sight or in the attic pouring down on your carpet and furniture?
And that's why we place the plumbing in the slab. Cheers. Tom