Chart of accounts (COA) importer does not import summary accounts

When creating a new client the Chart of accounts (COA) importer does not import summary accounts.

Steps to reproduce:

• Create a new client with the "Intial client" setup. Select the 'AccountingUS.csv' as the COA definition file.

• Login to the new client as admin.

• Go to the "Import File loader".

• Select the "AccountingUS.csv" file to load.

• Select "Accounting - Accounts" as import format.

• Import the file.

• Go to "Account element".

Expected result:
See a hierarchy (tree) of accounts with accounts having summary accounts above them. Just like in GardenWorld.

Actual result:
A flat list of detail accounts (account numbers with 5 digits) and all summary accounts missing.