You can A/B test pricing, Amazon does it all the time. You can have a pricing page that says "If this seems off to you, let us know and we'll talk" like Papertrail does. There are plenty of options, but if you're worried about customers walking away, you're losing tons of them by making them call you first.

Pricing is hard.

Your platform may have 1000's of features, not all of which all your clients want or can pay for. Packaging into simple groups may not possible until you have the volumes to figure out what works

Many clients need specific features that you don't have yet, pricing calculation becomes very complex, and depends on customer to customer as well. We will charge more to some customers simply because we know they need a lot of hand holding and special assistance

I don't run any business so I don't have much info, only questions. Why could you not simply add a "custom solution, contact us here" next to the publicly priced offers? That way everyone is addressed, best of both world.