Somehow you have to login now, to use it. It wasn't like this a few weeks ago...
That is not my experience, maybe your IP is flagged as hammering their site?
Oh, I wasn't aware of this. But how can you hammer a calculator? Yes, I have used it like 50 times, checking how big would be a Q4, or smaller model with different batch sizes and concurrent users. Do you think it is a heavy calculation?