The mathematical issue with your numbers is that until testing is consistently performed, that is the limiting factor. That was the case early in China.
Honestly, what you are measuring is the same as extrapolating the weight of a newborn baby.
I would be careful putting too much faith in growth rates until the testing is widespread.
Linking to journal articles on covid-19:
https://www.freerepublic.com/focus/f-chat/3823365/posts?page=1#1
Only tracking confirmed cases and their doubling rate.
Yesterdayay was 702 cases
If the doubling every two days holds, like it has again today, then tomorrow we’ll be 1404 total cases.
I’m doing simple stuff here.
And if the doubling of cases sticks to this rate, we can get an idea what next week looks like.
Any further extrapolations and inferences are left to experts