Earlier quoted context omitted.
No, sending a vague email that makes me waste my time to figure out how much more I have to pay them is unreasonable. They could have just included prices side by side and a sample invoice under the new system with the last month's usage
Does AWS do this ? Unless your using DO at a very large scale the pricing difference isn't significant. I personally use AWS now since my skills with AWS are useful at work as well. That's the biggest perk of AWS to me. At the same time I've always found AWS to have convoluted confusing billing, at least DO is straight forward even if it's gone up a buck or so.
AWS pricing can be confusing but they also offer significantly more services. I think it'd be more straight forward if they had the same number of products as Digital Ocean. Afaik they bill for the same things.