Accounting method seems to be missing from Summary

I’m setting up a new ‘official’ company in version 18.12.12. When I go to Summary to set the Accounting Method, there’s no option. My previous text company and Northwind both have it but not the new company. Have I done something wrong (or out of order) or is this a bug?

You now only get the accounting method option under Summary after a Sales or Purchase invoice has been created.

Thanks! I didn’t see that mentioned in the Guides.