Multifamily and Cost Segregation Studies

[Costin I.]

Inquiry to CSS, CPAs and MF experts:

Many sponsors of multifamily deals advertise the Cost Segregation study as a magic pill that creates money out of thin air, some claiming that by making one they will be able to return 40% of the investors money, even in the first or second year of the deal - how is that possible?

For all I know, a CSS only creates an acceleration of depreciation, that can be used to offset taxes on income. But that assumes you have that income from the deal, or similar. 

And then, if invested within a self-directed IRA, one can't take advantage of this depreciation. On that basis, the sponsor wants to redistribute the depreciation to "cash" investors only. Is that legal/possible?

And on the same basis, shouldn't then the UBIT be allocated only to same "cash" investors?

At the end of the deal lifetime ("selling in 5 years"), what happens with the depreciation (afaik it gets recaptured) ? And, is it correct/fair/legal to "be recaptured" by the entire pool of investors, or should be "recaptured" only from the "cash" investors that received said depreciation? 

Please help me complete/correct my understanding in these matters.