A: Yes it is normal, it won't send many requests while you type but it will send some to generate the audio to be played.
Generally, it's recommended to pre-compose your writing in Word or Google Docs before pasting / importing it to the app and edit it afterwards, that's the standard process that other users use and it's the most convenient. We also give a generous quota of 200,000 and 1,000,000 for this reason.
You can even set voice and settings beforehand using CSV import but that's for more advanced users.