I'd argue it's two different products with very different levels of support effort. Larger customers require much more time/effort than smaller customers. I could list an hourly rate, sure, but most customers don't even know where to begin with estimating how many consulting hours they'd need. I'd hate to lose a customer because they over-estimate the hours and think they can't afford it, or have them underestimate and be shocked later. Every customer is unique and there's no useful way to break it down into a pricing chart.
Let's say we charge everyone the "big customer" rate.. The smaller customers couldn't afford it. If we charged everyone the "small customer" rate, we'd put ourselves out of business by spending far too time on the big customers while not making enough revenue to cover the costs of serving the larger customers. If we're practical about it, the smaller customers just don't have budgets as large as the larger customers. If we want the smaller customers to buy in, we have to reduce the price to something that fits their budget.
I sympathize with big customers subsidizing small customers. That
premise applies to all percentage-based sales commission structures.
It's not clear whether showing a $1M mansion is any more work than
showing a $100k bungalow (certainly not 10X as much), but realtors obviously much prefer the former,
and will grudgingly take on the latter for portfolio reasons.
Let's say we charge everyone the "big customer" rate.. The smaller customers couldn't afford it. If we charged everyone the "small customer" rate, we'd put ourselves out of business by spending far too time on the big customers while not making enough revenue to cover the costs of serving the larger customers. If we're practical about it, the smaller customers just don't have budgets as large as the larger customers. If we want the smaller customers to buy in, we have to reduce the price to something that fits their budget.