The meter punishes success
A per-minute service around the typical $2 to $3 effective rate seems reasonable until you do a month's math. A hundred calls averaging four minutes is 400 minutes — call it $800 to $1,200, and that's a mid-sized month. The busier you get, the worse it gets. Your marketing works, your phone rings more, and your answering bill eats the gain.
Worse, the meter changes your behaviour. Owners on metered plans start hoping some calls don't come. That is a poisonous instinct to build into a business.
What flat-rate makes possible
When the price is the same whether fifty people call or five hundred, the phone stops being a cost centre. Every ring is pure upside. You put the number on everything, you invite calls, and you never look at a bill wondering which conversations were worth it.
It also aligns the incentives correctly: a flat-rate provider only wins if the desk is good enough that you stay. A metered provider wins when the clock runs.
The honest caveat
Flat rates only make sense when the provider's own costs are under control — which is exactly what modern voice AI made possible. The answering itself became inexpensive. What you're really paying for now is the part that never got cheap: a human being accountable for quality, reading every conversation, keeping the desk sharp.