What is the pricing revision for flexible resize option? How does it affect the transfer quota?

The price (cost) of the plan in the fixed tiers is very straightforward. But DigitalOcean offers “flexible resizing” option, in which case the configuration can be altered from the general fixed tiers to a customized option.

In this case, how is the pricing determined?

1. Pro-rated pricing based on actual resource configuration. (If so, what’s the split?)
2. Pricing based on the highest matching fixed tier for any of the resources.
3. Pricing based on the disk size (regardless of processor or RAM config)*

Additional Question: Does flexible resizing also increase or decrease the available transfer bandwidth? This is not mentioned anywhere in the related FAQs.

* I inferred this to be a possibility based on the bill PDF, where only the disk size is used to describe the server configuration and pricing unit used. Also, SSD is expensive.