Could you humor me for an example? What would the universe look like if "deontology is true" versus a universe where "deontology is false"?

What would it be like if utilitarianism is true? Or the axiom of choice? Or the continuum hypothesis?

I don't see how a deontological system would prevent number-crunching.

I don't see how a description of the neurology of moral reasoning tells you how to crunch the numbers -- which decision theory you need to use to implement which moral theory to resolve conflicts in the right way.