I’ve been through the tutorial and unfortunately been unable to confirm the difference you have observed. However I do think there is an issue in that when selecting “Strict” assessment (page 31), I only get 523 chemicals. When I do not select “Strict”, I get 689 chemicals as per the tutorial.
I can only think that maybe one or more of the Inventories is checked (page 29) under the Endpoint tab. When I check the TSCA Inventory, I get 1088 chemicals returned. So I’m wondering if any of these are checked on your system. If they are checked on a previous logon to the Toolbox, they stay selected until unchecked for all future logon's.
Non-Strict assessment with TSCA Inventory checked.
I hope this helps,