The described enterprise sales process sounds a bit odd to me. I come from the perspective of existing codebase that is tailored to the specific customer processes/org structure etc. so maybe it's different for a completely blue ocean type of product.

It's usually initial contact + demo or feature talk of sorts. The next step is some small project with customer specific data which is billed. They get a quote and either do it or don't. Scale up, SLA etc. follow after that (basic outline of what's possible is usually given in the initial contact). Alternatively this small project can be some consulting package but it's always billed.