Dbt Cloud Cost for Team Plan

I can see that for the Team plan in dbt cloud, it costs around $100/mo/seat. And also it has been mentioned Up to 8 developer seats and 5 read-only seats. So if we have around 10 developers, 8 developers seats would be given and 2 read only seats will be given?

Also read only seats are free of cost or does that also cost 100/mo/seat?

For example in the above case it should be 1000/mo/seat if we have 10 developers where 8 are developers seats and 2 is of read only seats.
Is my understanding correct?