elevated slab - monolithic slab or stem wall with slab on top?

[iSail2]

Hi all,

Using HD Pro 2014, I'm trying to decide which foundation method to use. I want to create an elevated slab, at least 12", so that I have about 2 or 3 steps up.

Should I go with monolithic slab and increase the slab thickness to whatever height I need? Don't know how to specify the footings yet. How do I deal with materials then: concrete and fill?

Or

Should I go with stem walls and footings and put a 4" slab on top of the stem walls? How do I account for the amount of fill needed (or should I even worry about that?)

Thanks in advance,
Elke